Did your Roku TV decide to strong arm you into giving up your rights or lose your FULLY FUNCTIONING WORKING TV? Because mine did.
It doesn't matter if you only use it as a dumb panel for an Apple TV, Fire stick, or just to play your gaming console. You either agree or get bent.
Recommendations to purchase a smart TV but never connect it to a network are futile, as well. Just like Amazon devices, smart TVs will find an open SSID and then phone home for updates without your knowledge.
My recommendation, when these kind of topics come up, is: either exchange your smart TV for a dumb one, or go to an electronics repair shop to have a board or two exchanged (depending on the make and model, older dumb components may be direct-ish replacements for smart ones).
EDIT: Another option? Try a projector! I was looking for dumb TV options online after writing up this comment, and someone on an old Reddit post recommended it. Great idea.
2nd EDIT: Someone else also recommended buying digital signage, another solid dumb display option.
Not necessarily. Never connecting it to the internet is much better advice than trying to block it's connections. After that it's not (usually) difficult to open the back of the TV and simply disconnect the wifi adapter itself. In my experience it's either a separate board connected by a ribbon cable or the same type of wifi adapter that is commonly found in laptops. If the antennas can be accessed then so can the adapter.
Yes, great advice. Open a high voltage device and play with its internals while voiding your warranty instead of checks notes... not giving it your Wi-Fi password.