PSA: Supabase Auth is based on their fork [0] of Netlify's Gotrue [1]. If you are migrating out of Supabase completely you can just drop in Gotrue for authentication.
We switched to Clerk.dev. Thankfully we had only supported magic link auth, so there wasn't much information to migrate over. Clerk has been pretty good - they have a great Remix integration and solid admin experience.
