Thanks for this info, just wanted to share that the image for the "Linux v6.1 vendor IOT image for the 5 "Max" model" you linked to also worked for me on my Orange Pi 5 Ultra with no modifications needed.
I haven't tested wifi or any use cases besides some simmple stuff over ssh so far, I did get a warning on first boot that it's a developer version of Armbian and shouldn't be used for production, but I suppose that's the case for all "community" builds?
I also found this gist with steps to build Armbian from scratch for the 5 Ultra, but I haven't tried this yet. In case anyone else is looking for related info this PR also is also relevant: https://github.com/armbian/build/pull/8252
I still regret not buying a better supported board like the 5 Max board instead but hopefully better support will come for the 5 Ultra with time.
