No video from VM if iGPU not connected to monitor. Must BOTH Intel iGPU and discrete GPU be connected?

[jce]

I have a monitor connected to the Nvidia card in my Proxmox box and have successfully passed it through to a Linux VM. However I find that I must also have the onboard Intel iGPU connected to the monitor for it to work (even if not switched to that input on the monitor), otherwise I just get a black screen when starting the VM. Is that to be expected or would I need to tweak my settings by, say, blacklisting the Intel iGPU as well? To get passthrough to work at all I needed to disable "multi-monitor" support and set the iGPU as the primary graphics in the motherboard BIOS

My hardware setup is:
Motherboard: Asrock B460M-ITX/ac
CPU: Intel 10100
GPU: Nvidia 1650 Super

/etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt pcie_acs_override=downstream,multifunction vfio_iommu_type1.allow_unsafe_interrupts=1 nofb nomodeset video=vesafb:off,efifb:off"

/etc/modules
vfio
vfio_pci
vfio_virqfd


/etc/modprobe.d/blacklist.conf
blacklist radeon
blacklist nvidiafb
blacklist nouveau
blacklist nvidia
blacklist i2c-nvidia-gpu


/etc/modprobe.d/pve-blacklist.conf
blacklist nvidiafb
blacklist nvidia
blacklist radeon
blacklist nouveau
blacklist i2c-nvidia-gpu


/etc/modprobe.d/kvm.conf
options kvm ignore_msrs=1


/etc/modprobe.d/vfio.conf
options vfio-pci ids=10de:2187,10de:1aeb disable_vga=1


/etc/pve/nodes/proxmox/qemu-server/<vm_id>.conf
agent: 1
args: -cpu 'host,+kvm_pv_unhalt,+kvm_pv_eoi,hv_vendor_id=NV43FIX,kvm=off'
bios: ovmf
boot: order=scsi0;ide2
cores: 6
cpu: host,hidden=1,flags=+pcid
efidisk0: local-lvm:vm-100-disk-1,size=4M
hostpci0: 01:00,pcie=1,x-vga=1
ide2: none,media=cdrom
machine: q35
memory: 12288
name: PopOS
net0: virtio=1E:04:B2:84:57:2A,bridge=vmbr0,firewall=1
numa: 0
ostype: l26
scsi0: local-lvm:vm-100-disk-0,backup=0,size=160G
scsihw: virtio-scsi-pci
smbios1: uuid=2a03a4df-c246-4c20-b2ce-bfbececc9869
sockets: 1
usb0: host=045e:07fd,usb3=1
usb1: host=05ac:0220,usb3=1
usb2: host=8087:0aa7,usb3=1
vmgenid: c8f92ced-90d0-47a6-b293-28ed7e1a77be