Comment by kup0

I'll give you my anecdotal experience with a TV that has Amazon's FireTV built-in. It is disconnected from any network. It allowed me to set a setting that says "remember last input" so it always looks at a particular HDMI input for signal when it's turned on (because I always have it set to viewing input, not the smart interface itself). Set like this, it essentially acts as a non-smart TV.

The only downsides are that, being a smartTV, even in this pseudo-non-smart mode, if the TV loses power (rather than just being in an "off/standby" state) then it takes a bit longer for the TV to start up the next time. I wish I could avoid a TV having a "boot sequence", but my experience is close enough to a non-smart TV that it works for me