Hi @Pixel,
If you’re planning on using a USB Ethernet adapter, be aware that you’ll need to make sure that sys-net has access to the USB device.
One way to do that is to select the option Use sys-net qube for both networking and USB devices during the Qubes OS setup, just after installation.
Use sys-net qube for both networking and USB devices: You should select this option if you rely on a USB device for network access, such as a USB modem or a USB Wi-Fi adapter. (source in the docs, with more context)
Besides that, I know for a fact that some work without issues; that may depends on the model. I may be wrong, but I wouldn’t expect the fact that the adapter has an USB-C interface would much difference to any other USB. I’d also expect most Ehternet devices to be well supported. Again, I may be wrong. If anyone knows better, please correct me!
Related topic: Ethernet through usb-c