I never connected my smart tvs to the internet. I buy the cheapest TV (at the size I want) and connect an old laptop, lid closed, and a cheap mini keyboard. It does everything I want, never updates itself with unwanted features and never shows me ads. Been doing this for 10 years, why would anyone actually want a smart tv.
I'm not saying you need a smart TV, but if you want to get the content you're actually paying for via Netflix, HBO etc in the highest quality they offer, you'll need to fork over money for a device with dedicated hardware