So both Ubuntu 22.04 and 20.04 installed and worked fine, in terms of graphics, using the standard Nouveau drivers - however no support for HDMI audio (a show stopper for me). I tried to install the proprietary Nvidia drivers, which wasn’t possible without rolling back to 20.02 and ended in an ugly mess (errors during install and not possible to boot without black screen crashes so I ended up just reinstalling). Think I reached 8 or 10 fresh installs of different Ubuntu releases before giving up. I didn’t try 22.10 though as this came out after I gave up.
But using open core patcher to install Monterey - that worked first time and so far seems to be working perfectly, and with beautiful Multichannel 24 bit 192kHz audio output (which I believe the newer Minis no longer support)
So to answer your question - no thanks, I am 99% confident that ROCK won’t support HDMI audio on the GeForce 320M graphics card. See also this self-solved support post for more details on why. Happy to be corrected if you know better though!! Also super happy with the support received from the tinkering community 
https://community.roonlabs.com/t/no-audio-output-from-2010-mac-mini-hdmi/215976