The plot thickens... I tried to attach it to a newly installed OpenMediaVault 4 VM, and it wouldn't start. I tried to run the command from shwocmd manually and I get this:
kvm: -device vfio-pci,host=43:00.0,id=hostpci0.0,bus=pci.0,addr=0x10.0,x-vga=on,multifunction=on: vfio error: 0000:43:00.0...