It works...
IT WORKS...
And I who thought that my Qubes OS was broken!!!
I can finally relax now!
BUT...
this guide https://mullvad.net/en/help/wireguard-on-qubes-os
may need an update like that if there is a resolvconf error on line 31 or 32 then suggest to the user to install resolvconf
sudo apt-get install resolvconf
