The other person said to never connect to wifi, but I’d say either put it on an isolated wifi (guest network) and lock it down to LAN-only access in your router, if at all possible.
The reason being that these devices are aggressive about getting a wifi signal, and even if they can’t connect to yours, they’ll apparently search for unprotected wifi networks and connect to those to send data and phone home. Locking it down to LAN only prevents this, and isolating to a guest network means no information about other devices on your network.
It’s utterly insane we have to do this stuff. If you’re willing to spend more, there are commercial signage displays you can buy that are essentially dumb TVs, and that is pretty much the only way to get a dumb TV today (and obviously, don’t expect smart features from it).
