Have you compared authentik to authelia by any chance? I use authentik but don’t think I’ve ever tried authelia. I did use keycloak for a bit too.

Are you saying you can import chat history with a bridge some how? I don’t remember that being an issue, but would be very handy

I’d also recommend Authentik. It’s simpler than something like keycloak imo and works pretty well. They also have guides for quite a few self hosted services.

I did have issues with it being slow at some point, but an update fixed it iirc.