How to keep your TV from spying on you:

Take the back off, look for a wire that goes to a small module which generally is at the top or the bottom edge.

Unplug it and tape it down. The TV will assume the wifi card failed and will continue to operate just fine.

Smart TV features will no longer work, which is what you want.

If you ever need to update the firmware you can always plug in the RJ-45 jack to a router, then unplug when finished.

 

All "Smart" TV's will still sniff the internet via wireless when getting ads and sending your viewing habits to them as part of their profit schemes, even if you turn off wifi on the TV.