Yes. All of them!

The battery of OP5T can't be removed. May need to either replace it with a "dead" battery or muck about with the software to make to never charge over 80%.

Thanks for this suggestion.

Can't remove battery. Will will try to put in a dummy battery if possible.

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.

Never heard of this academia stack exchange. Thank you.

Nothing there and as I wrote in another comment here, I think the mainline doesn't have the necessary drivers for this.

When testing the Ethernet, I didn't put power. I wanted to isolate each variable at a time.