I’ve been using Authentik for a while now and it works very well. There is also a Teraform provider to manage it as code. I do mostly OIDC, but also use it as a proxy for a few things that do not support that and just need to be locked down (Esp home and longhorn dashboards for example).

The disadvantage is that it is not the lightest option. If that is important to you, look at Authelia.