This is awesome! I literally gave better-auth a spin 2 days ago and I was able to get it up and running within 15 minutes. I'm yet to try the plugins, but looks really easy to set up and work with, safe to say I'll be using it for future projects.
I didn't like the fact that it doesn't have a built-in sign-in ui components, but glady https://github.com/daveyplate/better-auth-ui solves it.