Most new TVs are smart TVs so even if you do this you are still running on like Samsung have been caught screen capturing your TV and phoning home for advertising.
But when everyone keeps buying ""smart"" TVs and accepting the spyware, pretty soon they will start shipping with baked in 4G chips, and there will be no other option. Vote with your wallet by never buying a smart TV under any circumstance. They are cheaper than actual TVs because the data collected is so lucrative - buying one is implicitly supporting that slimy business model, even if you don't connect to WiFi.
How would they phone home without your help? If you're going the route suggested above then it would make no sense to bother putting your Samsung TV on the WiFi