So progress... I have changed my qemu entries to:
args: -device vfio-pci,host=00:02.0,id=hostpci0,bus=pci.0,addr=0x02,x-igd-gms=1,x-igd-opregion=on,romfile=/usr/share/kvm/i915ovmf.rom
This removed most of my errors, so I'm down to:
pve-test kernel: vfio-pci 0000:00:02.0: vfio_pci: Failed to...