I work at a radio observatory where we have extremely strict RFI rules. In our accommodation (40km away from the observatory) there's no WiFi allowed, but we are able to use normal computers etc.
We found that if you use an apple lightning to USB camera adapter, plugged in to a powered USB hub, and then plug an apple USB to ethernet adapter in to the hub, you get ethernet on the ipad, even though a dialog box comes up saying "this accessory is not supported".
It's clunky, but works, and is the only way I can get ethernet on my ipad while respecting our strict radio emissions rules.
Alas the same technique doesn't work at all on my iphone.