I have a Linksys wireless mesh system, but have a shed about 35m away. I couldn’t be bothered to wire. It has mains electricity so a power line link may have worked. But as it was only for streaming to Google speakers the wireless works well. Link from an upstairs window frame to the shed(wooden). If it’s only the last 30m would probably work.

They have restrictions for their reasons. Working around them would probably be a disciplinary issue.

Send them back, with a polite “no thanks” if you wish