I have added a PCIe Wi-Fi card to my Dell Xeon workstation, and it is working very well indeed.
I bought one of these: Amazon.co.uk, advertised as being Linux compatible. It was automatically recognised as such in lspci. The only action taken, post-installation, was to add it to sys-net unde the device tab.
So, Wi-Fi comes up when the system boots, much like Wi-Fi on other systems. My Qubes OS laptop has three red signal bars and a final signal bar that is a bit pink. My Qubes OS Xeon workstation now has four red signal bars.
Loose ends. The card was advertised as using the Intel AX210 chip set and being Linux compatible, whereas other cards with the same chip set were not adverised as being Linux compatible, only Windows compatible - are the anufacturers being defensive? Is there a security risk with setting up Wi-Fi this way? - not an issue in my circumstances.