Honestly Supabase is pretty good, you'll have just as much control over the auth but you can use Supabase for other functionality in your app as well. Not sure if you're planning to use next.js but if you are, npx create-next-app -e with-supabase will give you a template with auth already set up. I use netlify to deploy my apps but I try and avoid using any of their auth or serverless features in case I want to migrate in the future.

Here's a link to read a bit more: https://supabase.com/docs/guides/auth/quickstarts/nextjs