LDAP works fine, OIDC not so much, only the web client would work.

There are still talks around making OIDC a first class citizen and IIRC it is planned as per the feature page but I guess the major core upgrade around the DB took a lot of attention the last 6-12 months.

But in the meantime I've just spun up an LDAP outpost for my Authentik that my Jellyfin connects to. It breaks MFA but otherwise it works. It may be a bit confusing for users that they log in at jellyfin.site.com but anything user-related like updating password is at authentik.site.com and requires an extra login.