I’ve used that post as my guide to set up WiFi as well for AC9560 and AX200 cards. So I’m not sure what the exact issue you are facing.
5.9.14 should be no different from 5.8.11 in this case.
I’d like to just confirm a few things:
What template is sys-net running on? Fedora32 or Debian10 (or older if using Fedora 30/31 if on 4.0.4). Base template or any additional packages on these?
qvm-prefs sys-net ‘nopat iommu=soft swiotlb=8192 iwlwifi.disable_rxq=1’
Please double check your kernel options as you reversed the equal and underscore.
Also double check kernel is set properly in GUI, Network controller is passed through, and the VM is set to HVM.