try npmrc

apps/cms/.npmrc

@@ -0,0 +1,3 @@
+# Override workspace config to allow sharp to build platform-specific binaries
+# This is required for Payload CMS to work correctly on Vercel
+ignored-built-dependencies=

apps/cms/vercel.json

@@ -1,4 +1,4 @@
 {
   "buildCommand": "pnpm vercel-build",
-  "installCommand": "pnpm install --include=optional"
+  "installCommand": "pnpm install"
 }