That would be lovely. Unfortunately, to the best of my knowledge, nobody sells (for instance) high-quality 65"+ OLED non-"smart" TVs. "dumb TV" options are limited to older display technology.
Literally my current computer monitor, but no, does not work as a living room TV. (Also, would not recommend as a monitor; aggressive ABL and persistent messages about turning off for maintenance.)
When I said 55+ I was talking about the whole size category larger than that, including 65, 77, etc.
I have a 43" Philips Ambilight (43PUS8510, 4K QLED). It's not a dumb TV per se, but you don't have to use any of the smart features, and - most important - you don't have to connect it to a network.
I bought a Sceptre a few years ago but it died pretty quickly (dead pixel strip on the screen). But the replacement 44" Insignia (Best Buy) that I replaced it with has been an awesome tv.
So yes, you can just walk into the Electronics Store (Best Buy) and purchase a dumb TV.
I don't understand why the best advice in this thread is getting downvoted. Even if you buy a smart TV and then disable the smarts, you're still teaching the TV companies that smart TVs sell.