Even a smart TV is dumb enough if you use it as HDMI out for your actual streaming device (Chromecast, Roku, Apple TV, whatever) and never connect it to the internet. There were rumors about smart TVs connecting to unsecured wifi networks a few years ago, but I don't remember any verified cases or TVs.

This is the way. Allowing appliances to connect to the internet, when it's not necessary, is insecure.

At least with a single-purpose device, you know you're not at the mercy of some minimally-funded, likely-outsourced software team inside a hardware manufacturer.

I bought the 2025 Samsung smart TV that RTINGS recommended as the best OLED and connected it once at first setup to download updates. Then I blocked it in the router and disconnected it in the TV menu and it’s been smooth sailing. Everything goes through my Apple TV and there’s no ads and it just works.