Solved
I had to boot the Librem 14 with the Wifi killswitch disabled (allowing Wifi device to be powered on) in order for it to show up in the sys-net Qube Settings as an attatchable device. Then I could see it and attach it the sys-net Qube.
The Wifi killswitch on the Librem 14 behaves differently than the Wifi killswitch on the Librem 13. On the Librem 13, I could start the sys-net vm with the killswitch enabled (blocking Wifi device) and use the killswitch to change states while the sys-net vm was still running. On the Librem 14, if I attempt to start the sys-net vm with the Wifi killswitch enabled (blocking Wifi device), I get an error that the sys-net vm could not start because the Wifi devices was not attached (even though the ethernet device is attatched). And if I enable the killswitch (blocking Wifi device) while the sys-net vm is running, the sys-net vm goes from 0% CPU to 50%-60% CPU, and switching the killswitch back to allow the Wifi device does not make the Wifi device re-attatch.
Could someone from Purism (or someone else that understands this issue) comment on why the Librem 14 behaves this way?