I like Authentik, although I really like:

• Support for every auth protocol, particularly OIDC and LDAP
• Invites that can invite multiple people, letting me onboard a room of people at once
• Python based scripting that lets me script some integrations and do API calls when users authenticate

But at the same time, Authentik is very, very complex.

If you just want LDAP and OIDC in the same app, I would probably recommend KanIDM. KanIDM also does invites (although only one user at a time).

If you just want OIDC itself, pocket ID (passwordless /passkey only) and void auth both are really simple OIDC providers (that also support sign ups/invite links.

I am also paying attention to (some less popular options):

• Rauthy: Fairly minimal, supporting OIDC… but also supports PAM for Linux/Unix integrations
• Casdoor: seems to be feature rich like authentik, but perhaps not as difficult to deploy and configure
• Univention Nubus: An open source, European auth software, that is feature rich, but has an appliance virtual machine that might make it easier to install.