Not the OP but I started with cookie based auth and Spring Security and then moved to OAuth 2 - it’s extremely painless to setup (100 lines of code at most) but

Not the OP but I started with cookie based auth and Spring Security and then moved to OAuth 2 - it’s extremely painless to setup (100 lines of code at most) but it did take a while to understand it all. The Baeldung Spring Security course helped a lot. If in a hurry though you can always use an external service like Auth0. I had that setup in an afternoon whereas understanding OAuth 2 and Spring Security took a week.