I doubt errors like this are related to xen, but I could be wrong.
It just seems like there is some combinations of Qubes + motherboard + other random hardware that doesn’t work out of the box, and the same combination can be confirmed working with traditional Linux.
Which is why I said there are limited resources, it’s not realistic to expect the devs to solve all issues of this nature. Some of the issues might be trivial, others might not, but fixing and testing even trivial issues can be time-consuming/impossible without access to the hardware.
I think that some people make the mistake of thinking that if the chipset works on one motherboard, it will work on all motherboards. Just because the ASUS ArtPro B550 works, that doesn’t mean all B550 boards will work.