I think it shouldn't be too hard. I could even add Remix support for you if you wanted to do a contract (I am not able to do major open source work for free right now.)
- Cognito: bad
- Clerk: ok for small scale applications but they're a small company 'moving fast and breaking things'. It's not stable enough for a enterprise grade product that needs robustness.
- Auth0: Good but can get expensive
- WorkOS: Good for B2B, especially if 'directory syncing' is important for your usecase
authentication is critical, you shouldn't be outsourcing this stuff anyhow. learn how to harden your box, use cloudflare tunnel and dont store passwords in plaintext.
its really not hard to do and constantly being gaslighted into paying someone to do it for you because everybody else is doing it is just irresponsible.
I guess one clear difference is the lack of a marketing department from something well funded. I recall another HN comment here that said the best business model is to take something people can do already and mark it up by selling the pain points, that could be whats also helping all these auth as a service vendors.
Go with a proven, vetted, and trusted open source solution.