Bro, this is awesome. I have the feeling that because the amount of different boards Radxa has, the focus on Rock 5B has become less of a priority as they have given the users just the basics to start with.
I have also two boards both 16 GB and i really wanted to have Ubuntu 22.04 server jammy running on them, but no real good images to be found out there. As you have a Rock 5B yourself i have more hope like you said you want it to thrive.
I was reading anoher topic and there it was said that basic ethernet support in u-boot is now supported. Is this a possibility that we can maybe get it to work? I am not sure if it is done through firmware updates or so?
The reason i am asking this, is that both of my boards i still have not put them in the metal case because if i want to put a different OS on it, i have to disassemble the whole board to get to the M.2 Nvme SSD so i get put the new image on.