So let me recap:

- you want to start with USB3 (for which we have no support except maybe the USB2 fallback mode) to connect M.2/miniPCIe (again not really supported by anything) and then connect an atheros devices (do they even come in such modern form factor?).

Plenty of MorphOS supported HW does have Wifi onboard (or it can be added with the PowerMacs). Atheros cards exist in form factors natively supported by many other HW options and AFAIR there is even 1 type of wifi-USB-stick supported.