One option could be to get one of those 5G modems. It would require you to pay for your own Internet service, but many will then provide an Ethernet connection as an option, meaning you would never have to accept the legal terms presented to you. You could even use Wi-Fi because technically you never agreed to the terms, and practically speaking so many devices generate Wi-Fi networks I think it would be hard to enforce that you don’t produce any networks. Printers, smart watches, IP cameras… Are they really going to wardrive and triangulate the position of wireless devices on a regular basis? A sneaky network named after a printer or hidden SSID combined with ignorance for a TOS you never agreed to would probably slip through the cracks.
They don’t own the spectrum. I’m not sure it’s even legal to mandate that you can’t use Wi-Fi devices as long as you’re not using their network. When I was in university, there were still tons of such devices emitting signals that weren’t connected to the university network despite policy.