In addition to Supabase Auth the sibling mentions (which I played with very briefly) I've been using clerk.dev (no affiliation) and it's great. Depending on your definition of doing it yourself it could be just want you want. You have to set some things up, you're not going to get things like row-level permissions you get out of the box w/ Supabase, but if you're looking for a quick implementation where things like password reset etc. are handled for you, it might be a good fit.