Easy; Don't buy a TV with Roku. Dumber smart TVs are still a hassle, but I haven't heard of one that requires activation (yet).

Anecdotally, my Samsung projector wanted me to connect it to the WiFi. I told it to fuck off and connected a Shield to it (probably going to replace it with a beelink soon). It has a large green banner across the top when I go for the menu, but I almost never do that.

My friend got the same projector, set everything up, and the fucker displays ads. Seriously, what the fuck. I'll take the green bar.

Bought a Panasonic with Android TV about a year or two ago, and used it for a while solely as a screen for my Kodi box, no internet connection. Worked perfectly. The TV's image quality leaves something to be desired (especially backlight uniformity), though.

The last time I activated a TV was in 2022. It was a Sony X85K and it didn't require a connection. I've subsequently only used it with a CCwGTV.

Before that I activated a Samsung U..7300 or something like that in 2020. That didn't require connection either. I also used it with a CCwGTV.

I have two Vizio panels, a 2017 and a 2023. Neither are connected to my network. The 2017 got a couple of firmware updates via wired connection in the first year but I nixed that after an update nearly bricked it. The 2023 will turn itself back on for a few seconds occasionally (just the electronics, not the panel)... possibly looking for an open network but I have no way to verify. Neither complain about a lack of connection unless I accidentally select their streaming input.

I just moved and wound up getting an LG C4 65", put off getting internet service, TV worked fine