diff --git a/packages/payload/src/config/__tests__/sanitize.spec.ts b/packages/payload/src/config/__tests__/sanitize.spec.ts
new file mode 100644
index 00000000000..1c0377f1b79
--- /dev/null
+++ b/packages/payload/src/config/__tests__/sanitize.spec.ts
@@ -0,0 +1,37 @@
+import { describe, expect, it } from 'vitest'
+
+import { sanitizeConfig } from '../sanitize.js'
+
+describe('sanitizeConfig', () => {
+  it('should populate collectionsBySlug map from collections array', async () => {
+    const config = await sanitizeConfig({
+      collections: [
+        { slug: 'posts', fields: [] },
+        { slug: 'users', auth: true, fields: [] },
+      ],
+      globals: [{ slug: 'settings', fields: [] }],
+    } as any)
+
+    expect(config.collectionsBySlug).toBeInstanceOf(Map)
+    expect(config.collectionsBySlug.size).toBe(config.collections.length)
+    expect(config.collectionsBySlug.get('posts')).toBe(
+      config.collections.find((c) => c.slug === 'posts'),
+    )
+  })
+
+  it('should populate globalsBySlug map from globals array', async () => {
+    const config = await sanitizeConfig({
+      collections: [],
+      globals: [
+        { slug: 'settings', fields: [] },
+        { slug: 'nav', fields: [] },
+      ],
+    } as any)
+
+    expect(config.globalsBySlug).toBeInstanceOf(Map)
+    expect(config.globalsBySlug.size).toBe(config.globals.length)
+    expect(config.globalsBySlug.get('settings')).toBe(
+      config.globals.find((g) => g.slug === 'settings'),
+    )
+  })
+})
diff --git a/packages/payload/src/config/sanitize.ts b/packages/payload/src/config/sanitize.ts
index e65799c6e6d..b781dca175e 100644
--- a/packages/payload/src/config/sanitize.ts
+++ b/packages/payload/src/config/sanitize.ts
@@ -4,7 +4,12 @@ import { en } from '@payloadcms/translations/languages/en'
 import { deepMergeSimple } from '@payloadcms/translations/utilities'
 
 import type { OrderableJoinInfo } from '../fields/config/sanitizeJoinField.js'
-import type { CollectionSlug, GlobalSlug, SanitizedCollectionConfig } from '../index.js'
+import type {
+  CollectionSlug,
+  GlobalSlug,
+  SanitizedCollectionConfig,
+  SanitizedGlobalConfig,
+} from '../index.js'
 import type { SanitizedJobsConfig } from '../queues/config/types/index.js'
 import type {
   Config,
@@ -460,15 +465,6 @@ export const sanitizeConfig = async (incomingConfig: Config): Promise<SanitizedC
     config.csrf!.push(config.serverURL!)
   }
 
-  const uploadAdapters = new Set<string>()
-  // interact with all collections
-  for (const collection of config.collections!) {
-    // deduped upload adapters
-    if (collection.upload?.adapter) {
-      uploadAdapters.add(collection.upload.adapter)
-    }
-  }
-
   if (!config.upload) {
     config.upload = { adapters: [] }
   }
@@ -504,5 +500,18 @@ export const sanitizeConfig = async (incomingConfig: Config): Promise<SanitizedC
 
   await Promise.all(promises)
 
+  const collectionsBySlug = new Map<string, SanitizedCollectionConfig>()
+  for (const collection of config.collections as SanitizedCollectionConfig[]) {
+    collectionsBySlug.set(collection.slug, collection)
+  }
+
+  const globalsBySlug = new Map<string, SanitizedGlobalConfig>()
+  for (const global of config.globals ?? []) {
+    globalsBySlug.set(global.slug, global)
+  }
+
+  ;(config as any).collectionsBySlug = collectionsBySlug
+  ;(config as any).globalsBySlug = globalsBySlug
+
   return config as SanitizedConfig
 }
diff --git a/packages/payload/src/config/types.ts b/packages/payload/src/config/types.ts
index 8bbfcbf8eb3..949638be3be 100644
--- a/packages/payload/src/config/types.ts
+++ b/packages/payload/src/config/types.ts
@@ -1586,10 +1586,12 @@ export type SanitizedConfig = {
   } & DeepRequired<Config['admin']>
   blocks?: FlattenedBlock[]
   collections: SanitizedCollectionConfig[]
+  collectionsBySlug: Map<string, SanitizedCollectionConfig>
   /** Default richtext editor to use for richText fields */
   editor?: RichTextAdapter<any, any, any>
   endpoints: Endpoint[]
   globals: SanitizedGlobalConfig[]
+  globalsBySlug: Map<string, SanitizedGlobalConfig>
   i18n: Required<I18nOptions>
   jobs: SanitizedJobsConfig
   localization: false | SanitizedLocalizationConfig
diff --git a/packages/plugin-ecommerce/src/index.ts b/packages/plugin-ecommerce/src/index.ts
index 1a5059719c6..3658f29ed88 100644
--- a/packages/plugin-ecommerce/src/index.ts
+++ b/packages/plugin-ecommerce/src/index.ts
@@ -1,8 +1,6 @@
 import type { AcceptedLanguages } from '@payloadcms/translations'
 import type { Config, Endpoint } from 'payload'
 
-import { deepMergeSimple } from 'payload/shared'
-
 import type { PluginDefaultTranslationsObject } from './translations/types.js'
 import type { EcommercePluginConfig, SanitizedEcommercePluginConfig } from './types/index.js'
 
@@ -311,41 +309,35 @@ export const ecommercePlugin =
       incomingConfig.i18n = {}
     }
 
-    if (!incomingConfig.i18n?.translations) {
+    if (!incomingConfig.i18n.translations) {
       incomingConfig.i18n.translations = {}
     }
 
-    incomingConfig.i18n.translations = deepMergeSimple(
-      translations,
-      incomingConfig.i18n?.translations,
-    )
-
     /**
-     * Merge plugin translations
+     * Merge plugin translations — only for languages the user has enabled.
+     * Plugins run before sanitize, so `supportedLanguages` may be undefined; sanitize will
+     * default it to `{ en }`, so we mirror that here. Plugin-ecommerce translations always
+     * win over user-provided ones for the `plugin-ecommerce` namespace.
      */
-    if (!incomingConfig.i18n) {
-      incomingConfig.i18n = {}
-    }
-    Object.entries(translations).forEach(([locale, pluginI18nObject]) => {
-      const typedLocale = locale as AcceptedLanguages
-      if (!incomingConfig.i18n!.translations) {
-        incomingConfig.i18n!.translations = {}
+    const supportedLanguageKeys = incomingConfig.i18n?.supportedLanguages
+      ? Object.keys(incomingConfig.i18n.supportedLanguages)
+      : ['en']
+
+    for (const lang of supportedLanguageKeys) {
+      const pluginEntry = translations[lang as keyof typeof translations]
+      if (!pluginEntry) {
+        continue
       }
-      if (!(typedLocale in incomingConfig.i18n!.translations)) {
-        incomingConfig.i18n!.translations[typedLocale] = {}
-      }
-      if (!('plugin-ecommerce' in incomingConfig.i18n!.translations[typedLocale]!)) {
-        ;(incomingConfig.i18n!.translations[typedLocale] as PluginDefaultTranslationsObject)[
-          'plugin-ecommerce'
-        ] = {} as PluginDefaultTranslationsObject['plugin-ecommerce']
-      }
-
-      ;(incomingConfig.i18n!.translations[typedLocale] as PluginDefaultTranslationsObject)[
-        'plugin-ecommerce'
-      ] = {
-        ...pluginI18nObject.translations['plugin-ecommerce'],
-      }
-    })
+      const typedLocale = lang as AcceptedLanguages
+      const existing = (incomingConfig.i18n.translations[typedLocale] ?? {}) as Record<
+        string,
+        unknown
+      >
+      incomingConfig.i18n.translations[typedLocale] = {
+        ...existing,
+        'plugin-ecommerce': pluginEntry.translations['plugin-ecommerce'],
+      } as PluginDefaultTranslationsObject
+    }
 
     if (!incomingConfig.typescript) {
       incomingConfig.typescript = {}
diff --git a/packages/plugin-import-export/src/index.ts b/packages/plugin-import-export/src/index.ts
index 2904f4abdf8..6d956b02069 100644
--- a/packages/plugin-import-export/src/index.ts
+++ b/packages/plugin-import-export/src/index.ts
@@ -191,15 +191,21 @@ export const importExportPlugin =
     }
 
     /**
-     * Merge plugin translations
+     * Merge plugin translations — only for languages the user has enabled.
+     * Plugins run before sanitize, so `supportedLanguages` may be undefined; sanitize will
+     * default it to `{ en }`, so we mirror that here to avoid merging 30+ unused tables.
      */
-    const simplifiedTranslations = Object.entries(translations).reduce(
-      (acc, [key, value]) => {
-        acc[key] = value.translations
-        return acc
-      },
-      {} as Record<string, PluginDefaultTranslationsObject>,
-    )
+    const supportedLanguageKeys = config.i18n?.supportedLanguages
+      ? Object.keys(config.i18n.supportedLanguages)
+      : ['en']
+
+    const simplifiedTranslations: Record<string, PluginDefaultTranslationsObject> = {}
+    for (const lang of supportedLanguageKeys) {
+      const entry = translations[lang as keyof typeof translations]
+      if (entry) {
+        simplifiedTranslations[lang] = entry.translations
+      }
+    }
 
     config.i18n = {
       ...config.i18n,
diff --git a/packages/plugin-search/src/index.ts b/packages/plugin-search/src/index.ts
index f7fcc27ac6f..883a7d13e16 100644
--- a/packages/plugin-search/src/index.ts
+++ b/packages/plugin-search/src/index.ts
@@ -22,11 +22,16 @@ export const searchPlugin =
     incomingPluginConfig.localize = shouldLocalize
 
     if (collections) {
-      const labels = Object.fromEntries(
-        collections
-          .filter(({ slug }) => incomingPluginConfig.collections?.includes(slug))
-          .map((collection) => [collection.slug, collection.labels]),
-      )
+      // O(1) slug lookup for enabled-collection checks; replaces an Array.indexOf in the
+      // hook-attachment pass that was O(M) per collection.
+      const enabledSlugSet = new Set(incomingPluginConfig.collections ?? [])
+
+      const labels: Record<string, (typeof collections)[number]['labels']> = {}
+      for (const collection of collections) {
+        if (enabledSlugSet.has(collection.slug)) {
+          labels[collection.slug] = collection.labels
+        }
+      }
 
       const pluginConfig: SanitizedSearchPluginConfig<ConfigTypes> = {
         // write any config defaults here
@@ -42,8 +47,7 @@ export const searchPlugin =
         ?.map((collection) => {
           const { hooks: existingHooks } = collection
 
-          const enabledCollections = pluginConfig.collections || []
-          const isEnabled = enabledCollections.indexOf(collection.slug) > -1
+          const isEnabled = enabledSlugSet.has(collection.slug)
           if (isEnabled) {
             return {
               ...collection,
diff --git a/packages/plugin-seo/src/index.ts b/packages/plugin-seo/src/index.ts
index dc81ce03bf9..0e0c2477dcd 100644
--- a/packages/plugin-seo/src/index.ts
+++ b/packages/plugin-seo/src/index.ts
@@ -55,6 +55,15 @@ export const seoPlugin =
       },
     ]
 
+    const collectionConfigBySlug = new Map<string, NonNullable<Config['collections']>[number]>()
+    for (const c of config.collections ?? []) {
+      collectionConfigBySlug.set(c.slug, c)
+    }
+    const globalConfigBySlug = new Map<string, NonNullable<Config['globals']>[number]>()
+    for (const g of config.globals ?? []) {
+      globalConfigBySlug.set(g.slug, g)
+    }
+
     return {
       ...config,
       collections:
@@ -144,10 +153,12 @@ export const seoPlugin =
             const result = pluginConfig.generateTitle
               ? await pluginConfig.generateTitle({
                   ...data,
-                  collectionConfig: config.collections?.find(
-                    (c) => c.slug === reqData.collectionSlug,
-                  ),
-                  globalConfig: config.globals?.find((g) => g.slug === reqData.globalSlug),
+                  collectionConfig: reqData.collectionSlug
+                    ? collectionConfigBySlug.get(reqData.collectionSlug)
+                    : undefined,
+                  globalConfig: reqData.globalSlug
+                    ? globalConfigBySlug.get(reqData.globalSlug)
+                    : undefined,
                   req,
                 } satisfies Parameters<GenerateTitle>[0])
               : ''
@@ -168,10 +179,12 @@ export const seoPlugin =
             const result = pluginConfig.generateDescription
               ? await pluginConfig.generateDescription({
                   ...data,
-                  collectionConfig: config.collections?.find(
-                    (c) => c.slug === reqData.collectionSlug,
-                  ),
-                  globalConfig: config.globals?.find((g) => g.slug === reqData.globalSlug),
+                  collectionConfig: reqData.collectionSlug
+                    ? collectionConfigBySlug.get(reqData.collectionSlug)
+                    : undefined,
+                  globalConfig: reqData.globalSlug
+                    ? globalConfigBySlug.get(reqData.globalSlug)
+                    : undefined,
                   req,
                 } satisfies Parameters<GenerateDescription>[0])
               : ''
@@ -192,10 +205,12 @@ export const seoPlugin =
             const result = pluginConfig.generateURL
               ? await pluginConfig.generateURL({
                   ...data,
-                  collectionConfig: config.collections?.find(
-                    (c) => c.slug === reqData.collectionSlug,
-                  ),
-                  globalConfig: config.globals?.find((g) => g.slug === reqData.globalSlug),
+                  collectionConfig: reqData.collectionSlug
+                    ? collectionConfigBySlug.get(reqData.collectionSlug)
+                    : undefined,
+                  globalConfig: reqData.globalSlug
+                    ? globalConfigBySlug.get(reqData.globalSlug)
+                    : undefined,
                   req,
                 } satisfies Parameters<GenerateURL>[0])
               : ''
@@ -216,10 +231,12 @@ export const seoPlugin =
             const result = pluginConfig.generateImage
               ? await pluginConfig.generateImage({
                   ...data,
-                  collectionConfig: config.collections?.find(
-                    (c) => c.slug === reqData.collectionSlug,
-                  ),
-                  globalConfig: config.globals?.find((g) => g.slug === reqData.globalSlug),
+                  collectionConfig: reqData.collectionSlug
+                    ? collectionConfigBySlug.get(reqData.collectionSlug)
+                    : undefined,
+                  globalConfig: reqData.globalSlug
+                    ? globalConfigBySlug.get(reqData.globalSlug)
+                    : undefined,
                   req,
                 } satisfies Parameters<GenerateImage>[0])
               : ''
diff --git a/packages/storage-s3/src/adapter.ts b/packages/storage-s3/src/adapter.ts
index 03a084c1e70..00f40962763 100644
--- a/packages/storage-s3/src/adapter.ts
+++ b/packages/storage-s3/src/adapter.ts
@@ -1,4 +1,4 @@
-import type * as AWS from '@aws-sdk/client-s3'
+import type { S3, S3ClientConfig } from '@aws-sdk/client-s3'
 import type {
   Adapter,
   ClientUploadsConfig,
@@ -7,17 +7,14 @@ import type {
 
 import type { SignedDownloadsConfig } from './getFile.js'
 
-import { deleteFile } from './deleteFile.js'
 import { generateURL } from './generateURL.js'
-import { getFile } from './getFile.js'
-import { uploadFile } from './uploadFile.js'
 
 interface CreateS3AdapterArgs {
   acl?: 'private' | 'public-read'
   bucket: string
   clientUploads?: ClientUploadsConfig
-  config: AWS.S3ClientConfig
-  getStorageClient: () => AWS.S3
+  config: S3ClientConfig
+  getStorageClient: () => S3
   signedDownloads: SignedDownloadsConfig
   useCompositePrefixes?: boolean
 }
@@ -45,17 +42,22 @@ export function createS3Adapter({
         useCompositePrefixes,
       }),
 
-    handleDelete: ({ doc: { prefix: docPrefix = '' }, filename }) =>
-      deleteFile({
+    // Helpers below dynamic-import their @aws-sdk dependencies so the SDK only
+    // loads on the first request that actually needs it.
+    handleDelete: async ({ doc: { prefix: docPrefix = '' }, filename }) => {
+      const { deleteFile } = await import('./deleteFile.js')
+      return deleteFile({
         bucket,
         client: getStorageClient(),
         collectionPrefix: prefix,
         docPrefix,
         filename,
         useCompositePrefixes,
-      }),
+      })
+    },
 
     handleUpload: async ({ data, file }) => {
+      const { uploadFile } = await import('./uploadFile.js')
       await uploadFile({
         acl,
         bucket,
@@ -72,11 +74,12 @@ export function createS3Adapter({
       return data
     },
 
-    staticHandler: (
+    staticHandler: async (
       req,
       { headers, params: { clientUploadContext, filename, prefix: prefixQueryParam } },
-    ) =>
-      getFile({
+    ) => {
+      const { getFile } = await import('./getFile.js')
+      return getFile({
         bucket,
         client: getStorageClient(),
         clientUploadContext,
@@ -88,6 +91,7 @@ export function createS3Adapter({
         req,
         signedDownloads,
         useCompositePrefixes,
-      }),
+      })
+    },
   })
 }
diff --git a/packages/storage-s3/src/generateSignedURL.ts b/packages/storage-s3/src/generateSignedURL.ts
index 8992b66f27b..5308dde3cb3 100644
--- a/packages/storage-s3/src/generateSignedURL.ts
+++ b/packages/storage-s3/src/generateSignedURL.ts
@@ -1,7 +1,8 @@
+import type { S3 } from '@aws-sdk/client-s3'
 import type { ClientUploadsAccess } from '@payloadcms/plugin-cloud-storage/types'
 import type { PayloadHandler } from 'payload'
 
-import * as AWS from '@aws-sdk/client-s3'
+import { PutObjectCommand } from '@aws-sdk/client-s3'
 import { getSignedUrl } from '@aws-sdk/s3-request-presigner'
 import { resolveSignedURLKey } from '@payloadcms/plugin-cloud-storage/utilities'
 import { APIError, Forbidden } from 'payload'
@@ -17,7 +18,7 @@ interface Args {
   acl?: 'private' | 'public-read'
   bucket: string
   collections: S3StorageOptions['collections']
-  getStorageClient: () => AWS.S3
+  getStorageClient: () => S3
   useCompositePrefixes?: boolean
 }
 
@@ -87,7 +88,7 @@ export const getGenerateSignedURLHandler = ({
 
     const url = await getSignedUrl(
       getStorageClient(),
-      new AWS.PutObjectCommand({
+      new PutObjectCommand({
         ACL: acl,
         Bucket: bucket,
         ContentLength: filesizeLimit ? Math.min(filesize, filesizeLimit) : undefined,
diff --git a/packages/storage-s3/src/index.ts b/packages/storage-s3/src/index.ts
index 5fbb0f3568d..e12c48aae8c 100644
--- a/packages/storage-s3/src/index.ts
+++ b/packages/storage-s3/src/index.ts
@@ -1,3 +1,4 @@
+import type { S3ClientConfig } from '@aws-sdk/client-s3'
 import type {
   ClientUploadsConfig,
   PluginOptions as CloudStoragePluginOptions,
@@ -6,7 +7,7 @@ import type {
 import type { NodeHttpHandlerOptions } from '@smithy/node-http-handler'
 import type { Config, Plugin, UploadCollectionSlug } from 'payload'
 
-import * as AWS from '@aws-sdk/client-s3'
+import { S3 } from '@aws-sdk/client-s3'
 import { cloudStoragePlugin } from '@payloadcms/plugin-cloud-storage'
 import { initClientUploads } from '@payloadcms/plugin-cloud-storage/utilities'
 
@@ -69,7 +70,7 @@ export type S3StorageOptions = {
    *
    * [AWS.S3ClientConfig Docs](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-s3/interfaces/s3clientconfig.html)
    */
-  config: AWS.S3ClientConfig
+  config: S3ClientConfig
 
   /**
    * Whether or not to disable local storage
@@ -106,7 +107,7 @@ export type S3StorageOptions = {
 
 type S3StoragePlugin = (storageS3Args: S3StorageOptions) => Plugin
 
-const s3Clients = new Map<string, AWS.S3>()
+const s3Clients = new Map<string, S3>()
 
 const defaultRequestHandlerOpts: NodeHttpHandlerOptions = {
   httpAgent: {
@@ -124,14 +125,16 @@ export const s3Storage: S3StoragePlugin =
   (incomingConfig: Config): Config => {
     const cacheKey = s3StorageOptions.clientCacheKey || `s3:${s3StorageOptions.bucket}`
 
-    const getStorageClient: () => AWS.S3 = () => {
+    const isPluginDisabled = s3StorageOptions.enabled === false
+
+    const getStorageClient: () => S3 = () => {
       if (s3Clients.has(cacheKey)) {
         return s3Clients.get(cacheKey)!
       }
 
       s3Clients.set(
         cacheKey,
-        new AWS.S3({
+        new S3({
           requestHandler: defaultRequestHandlerOpts,
           ...(s3StorageOptions.config ?? {}),
         }),
@@ -140,8 +143,6 @@ export const s3Storage: S3StoragePlugin =
       return s3Clients.get(cacheKey)!
     }
 
-    const isPluginDisabled = s3StorageOptions.enabled === false
-
     initClientUploads({
       clientHandler: '@payloadcms/storage-s3/client#S3ClientUploadHandler',
       collections: s3StorageOptions.collections,
diff --git a/test/plugin-ecommerce/int.spec.ts b/test/plugin-ecommerce/int.spec.ts
index ab2ba64ed4d..b1ca613b878 100644
--- a/test/plugin-ecommerce/int.spec.ts
+++ b/test/plugin-ecommerce/int.spec.ts
@@ -71,6 +71,23 @@ describe('ecommerce', () => {
     expect(variants).toBeTruthy()
   })
 
+  it('should only merge plugin translations for supportedLanguages', () => {
+    // The shared test buildConfig defaults supportedLanguages to { de, en, es }.
+    const supportedLangKeys = Object.keys(payload.config.i18n.supportedLanguages).sort()
+    expect(supportedLangKeys).toEqual(['de', 'en', 'es'])
+
+    for (const lang of supportedLangKeys) {
+      expect(payload.config.i18n.translations[lang]).toHaveProperty('plugin-ecommerce')
+    }
+
+    // Plugin must not pollute non-supported languages (e.g. ar, fr).
+    const arTranslations = payload.config.i18n.translations.ar as
+      | Record<string, unknown>
+      | undefined
+
+    expect(arTranslations?.['plugin-ecommerce']).toBeUndefined()
+  })
+
   describe('guest cart access', () => {
     it('should allow guest users to create carts', async () => {
       // Create a cart without authentication
diff --git a/test/plugin-import-export/int.spec.ts b/test/plugin-import-export/int.spec.ts
index 6923ce5ee5e..da6f0ff9a78 100644
--- a/test/plugin-import-export/int.spec.ts
+++ b/test/plugin-import-export/int.spec.ts
@@ -50,6 +50,25 @@ describe('@payloadcms/plugin-import-export', () => {
     await payload.destroy()
   })
 
+  describe('i18n scoping', () => {
+    it('should only merge plugin translations for supportedLanguages', () => {
+      const supportedLangKeys = Object.keys(payload.config.i18n.supportedLanguages)
+      expect(supportedLangKeys.sort()).toEqual(['en', 'es', 'he'])
+
+      // German is not in supportedLanguages — plugin-import-export must not contribute keys to it.
+      const deTranslations = payload.config.i18n.translations.de as
+        | Record<string, unknown>
+        | undefined
+
+      expect(deTranslations?.['plugin-import-export']).toBeUndefined()
+
+      // It should be present for supportedLanguages.
+      expect(payload.config.i18n.translations.en).toHaveProperty('plugin-import-export')
+      expect(payload.config.i18n.translations.es).toHaveProperty('plugin-import-export')
+      expect(payload.config.i18n.translations.he).toHaveProperty('plugin-import-export')
+    })
+  })
+
   describe('graphql', () => {
     it('should not break graphql', async () => {
       const query = `query {