Deploy turborepo project with api folder on vercel

I am building a backend project in my monorepo, which is using some internal workspace packages and api handler at apps/backend/api/index.ts. I was expecting the vercel to magically build the app, but getting bundle resolution errors:

Cannot find module '/var/task/apps/backend/node_modules/@recalio/db/index.ts'
Did you forget to add it to "dependencies" in `package.json`?
Node.js process exited with exit status: 1. The logs above can help with debugging the issue.

Project url: https://backend-recalio.vercel.app/api
Framework: just api folder with api handler exported.
Project settings: this is my vercel json file:

{
	"version": 2,
	"builds": [
		{
			"src": "api/index.ts",
			"use": "@vercel/node"
		}
	],
	"routes": [
		{
			"src": "/api/(.*)",
			"dest": "api/index.ts"
		}
	]
}

I am seeking guidance on how to resolve this issue or any similar experiences and solutions that others might have encountered in this community. Thank you for your assistance!

Are you able to provide a fuller reproduction?

For sure, here is a minimal reproduction: GitHub - Royal-lobster/turborepo-api-vercel. I’ve
hosted it on vercel at turborepo-api-vercel.vercel.app

Also i can’t use vercel dev for development, it errors with this non existent path