There’s SwiftFin, but it’s been a while from the last update (iOS app was updated recently though) and there’s a number of issues. It’s usable though (I’m using it).

There’s LaserWeb but apparently it doesn’t support closed source (Chinese) firmware so you’d need to change your laser’s controller…

The only alternative I know of that goes close to what FreeIPA does (minus the cert part) is kanidm. It does:

• oauth2
• ssh key distribution
• RADIUS
• PAM/SSSD
• LDAP

I just noticed they have a beta for multimaster replication, which is nice.

I use it at home. Note, though, that it does not do any hand-holding, and all configuration is done through CLI. Also note, there are docs for the stable or dev branch and there sometimes are big differences between the two.

I use kanidm with oauth2-proxy. No issues so far, it was pretty easy to set up.

Note that the connection to kanidm needs to be TLS even if you have a reverse proxy!

EDIT: currently using 80MB RAM for two users and three Service Providers.