Since there's not much of a spec (past users on newish devices), I would default to:

* Next.js - React on the frontend with endpoints handled by Next.js.

* Postgres for the DB

* Hosted on Vercel (unless otherwise specified).

* S3 for binary files.

If the project scope was anything past what Next.js APIs can reasonable handle (heavy DB migrations required, an admin panel, etc), I'd go with:

* Django Rest (or Django Graphene for GraphQL if it's a better fit) on the backend.

* React on the frontend (possibly still with Next.js if server-side rendering is high priority).

* Postgres for the DB.

* Frontend hosted on Netlify or Vercel.

* Backend hosted on Elastic Beanstalk, DB hosted on AWS Aurora, and S3 for binary files.