My plan to buy a TV is to get one that can be kept offline, or one that can be made able to stay offline through flashing or dismantling into its very core elements.
Dismantling it would probably ensure it's ugly af, but maybe if you try to go for one of those TV-in-a-frame things it might not look hideous.
Every smart TV I own can be kept offline; I just don't put it online ever. The issue is the software bloat makes turning them on unnecessarily slower.
Or you can either do what I do and buy an old TV. I have a nearly 20 year old plasma that looks great and isn't gonna listen in on me. If you absolutely need a higher resolution than 1080p or need an OLED display, you can buy them as "digital signage" (though, usually with a pretty high markup)
Not sure how common it is now, but based on repair manuals my TV's wifi is provided by a standard m.2 wifi module and can be trivially removed. That wouldn't stop them from changing the TV's OS to nag or otherwise disable itself afterwards but the hardware change is about as trivial as it could be.
Now why the disable wifi option isn't available on the TV when it appears in the user manual is another matter...