If that's the solution you're willing to deal with you can just not connect to the router in the first place. That's what I did with my new Fire TV but it does kill almost all the smart TV features like streaming and voice controls.
Honesty I just never connected mine to the internet and attached a Roku which I did connect. Smart TVs are anything but that, I rather have a dedicated media player than one bolted onto a screen.
Or just don't enter your WiFi password on it.
There were reports that some TV’s will automatically connect to any unsecured WiFi.
Our smart TV lives on it's own wifi network, I super don't trust it to interact nicely with other devices on our home network. All the other smart home stuff (smart led lights, etc) lives on it's own network as well.
But then it can self-update and install crapware without any interaction anyway.
I would but then I cant use netflix on it.
I wonder if it would be easier to just whitelist Netflix. But I suppose you've got the same dragon-chasing problem then, just inverted.
Buy a dumb TV and a chromecast was my solution to the problem. Chromecast works waaaay better than any half-assed built in smart situation anyway
Do dumb TVs even exist anymore?
Not really, but unless you are actually using the tuner for something you can get a monitor or commercial display, which is basically a dumb TV minus a TV tuner.
They typically cost more than smart TVs, but if you see them as more valuable because of avoiding unwanted functions, that's perfectly expected.