I guess it needs to be said again: “smart TVs” are cheap because of post-purchase monetization. That is: they gather your viewing and UI interaction behaviors (and, in some cases, ambient sound) for analysis and sale by the manufacturer.
The TV is a product, sure, but so are you when you use a “smart TV” like that without mitigating its connectivity by not letting it on your network and just using a discrete streaming peripheral of some sort instead.