Ask Wirecutter: Can you recommend a not-smart TV for me?

Yes! That’s exactly what I want! (Except replace “computer” with “Apple TV”).

RS-232 control also has a command to disable OSD, which has the pleasant side effect of disabling annoying smart TV bits like pop-up notifications even when the TV is connected to the Internet (and also superfluous [to me] non-smart TV pop-ups that ordinarily appear when switching inputs and adjusting visually apparent settings like brightness).

Disabling the OSD also disables the bundled Magic Remote, though IR remotes still work (unless locked out with another command) and OSD can be re-enabled via RS-232, or by simply power-cycling the TV.

As a bonus, input switching via IR remote (or RS-232) is noticeably faster than switching via Magic Remote, even if you set up hotkeys, as full-featured LG IR remotes have hard buttons for each input that don't require press-and-hold to activate (this includes sub-$10 service remote knock-offs on Amazon, which work perfectly fine IME, though you may want to steer away from these in a casual setting as some of the service buttons can cause undesirable behavior).

For my own use, I wrote a trivial ASP.NET Web API wrapper around the LG RS-232,

https://github.com/jasminetroll/LgTvControl

While only tested on macOS controlling the TV I own (55SK9000), the documentation it's written against isn't model-specific and I'm not using any platform-specific .NET APIs, so it should work across many TV models and on any platform that supports RS-232 and .NET (.NET 6.0+ as currently configured, though it was mostly developed on .NET Core 3.1, so changing TargetFramework in the csproj file should suffice to get it running on older versions).

My last TV purchase was a real shitshow ~5 years ago. As many are noticing, the manufacturers don't seem to want to make them. I ended up buying a supposed smart TV, but have never have given it access to the network, and disabled everything I could in it's interface.

I use a combination of Youtube-dl and OSMC to download content I want, without the commercials or ads. Luckily one of my local networks has a substantial youtube channel, so I got local content again, as well as PBS.

What for? I'd prefer to connect my own computer instead of having a worse one build in

It comes down to upgradability for me. The display is going to last far longer than the smart software running on it. Turning on my TV takes a full minute and a half before it will accept inputs from its remote, I've periodically connected it to the internet to check for updates and in two years there hasn't been a single one.

That's not true for every TV but in general my experience has been the built-in Roku, and other smart TV features are poorer quality than the stand alone sticks and either don't get updates at all or significantly less frequently. Because of the nature of these appliances they aren't as disposable so manufacturers have less incentive to provide those updates and high quality experiences as the stand alone products.

All that smart poor quality software on the TV itself compromises the core functionality of the TV itself which is being a good medium for the display of a user's choice content.