With 'lsusb', I can see the portonics being detected. But 'ip a' doesn't seem to show any valid Ethernet connection.
It seems you are right on the absence of correct drivers. I'll try the USB-debugging mode + router port approach to see if that works.
I would ideally want to leave this for the next couple of years without having to fiddle with it.
Nothing there and as I wrote in another comment here, I think the mainline doesn't have the necessary drivers for this.