We have a food trailer with a square register pos. It seems the only way to get a kitchen printer to work is via USB. Can you connect via the ethernet port on the USB square device
It's a possibility, Amazon has quite a few USB to Ethernet adapters available.
However, I'm pretty sure that's not something Square will support if you run into troubles.
If the printer is new, you may be able to contact the company you bought it from and ask to replace it for a USB version though. Just say it was your oops about what kind of interface it needed. Usually they'll work with you.
Square Community
Square Products