Qubes crashes on VM boot

I recently bought a system to run Qubes 4.2, but every time I boot a VM, the system hangs for a couple seconds, then immediately powers off and reboots. Originally I thought it was an issue handling PCI devices (some people seemed to have similar-ish problems relating to PCI passthrough with certain devices), but starting a VM with no passed-through devices results in the same behavior.

This results in a scenario where the Qubes initial setup consistently crashes. I can create qubes manually if I skip the initial setup, but I still can’t run any VMs without the system powering off. Ideally I don’t want to return the system, since the specs-to-price ratio are better than I expect to be able to find again. But if it can’t run Qubes I really don’t have an option.

I’m trying to run Qubes on a Lenovo Slim 7 Pro X laptop with a Ryzen 6000-series CPU. I know Qubes prefers legacy BIOS over UEFI, and I considered that as a possible source of the problem, though the firmware provides no option to boot via anything other than UEFI.

Is there anything relevant in journalctll -r in dom0?

I checked but couldn’t find anything that looks related. The system powers off without going through the shutdown process, so I assume it never gets the chance to write an error to the log. I couldn’t find any signs of it complaining about a hardware issue, either.

I ended up returning the system.