Firebase functions does not support monorepo structures (NPM monorepo, NX, Turborepo) during deployment.

Firebase uses custom archive logic for functions packaging (https://github.com/firebase/firebase-tools/blob/127ca3fbf7549d6c0cdf12e89e4465de9dd2b7c9/src/deploy/functions/prepareFunctionsUpload.ts), which does not support internal packages deployment out of the box.

Github discussion: https://github.com/firebase/firebase-tools/issues/653