hmm, in my case, ryzen 7600/asrock b850 pro-a, and rtx 3090, it works without any concerns with r2.4 with kernel-latest. no problems, what i initially did was just remove the card while preinstallation/postinstallation and adding it after first boot. setting kernal parameter for hide pci(see 'Creating Gaming HVM).
but, i have trouble installing 4.3 alpha. seeing HCL, trying to debug with it with gemini, nothing worked - i don’t have enough expertise to debug fully on my own. it seemed related to cpu/motherboard issue, since integrated gpu seemed cannot display the display manager. while first boot, adding both xen line and linux line to x2apic=false made it worked, but it seems weird that 1) qubes cannot recognize about 4 GB of ram and 2) it doesn’t display the display manager after second(third, forth, … ) boot. nvidia-troubleshooting doesn’t work at all.