How to check if sys-net has usb capabilities

Perhaps you can just check in the “services” tab of the sys-net settings if USB controllers attached to it?

As for the usb wifi adapter, I don’t know, but maybe this can help: USB-C Ethernet Adapters and How to connect to the internet in Qubes OS 4.0.3 using a USB modem ? · Issue #5610 · QubesOS/qubes-issues · GitHub