Sorry, I couldn’t manage to read the whole post. Anyway, you may want to try authentik 2024.6 or later. They “reworked proxy provider redirect” in that version. I find it much more stable, but still not perfect. OAuth works great though. Note that 2024.6 requires Postgre db upgrade.
Oh wow. SUSE family of distribution is relatively small footprint. Whole story sounds like “splitting the hair”. The only reasonable explanation is that SUSE hired some self-glorified marketer from big corp. omg…