If you just want it for the HDMI input to use as an aux screen for what ever computer your running than anything with an HDMI input in the size range you want should work. I run all the TV's in my house like this; connected to mac mini's instead of futzing with the onboard software mostly because I despise typing one letter at a time with a tv remote.
Honestly all the onboard TV OS stuff I have interacted with in the last decade has been more or less terrible and I wouldn't even consider it when buying a TV especially one that is just going to be a screen. All of the recent installs Ive dealt with (family and friend support) has revealed a ton of pay-to-play features (Samsung frame tv's cough cough). I applaud you for wanting something neat but I cant say Ive come across anything Ive ever actually wanted to use beyond "select input -> HDMI1"...
This, this, this.
Just never, ever connect the TV to the internet. Connect up an Nvidia shield, or a mini-PC/raspberry pi configured with whatever apps you desire, hidden behind a pi-hole. Connect a steam deck if gaming/linux desktop usage is your thing. I only touch the TV remote to switch on the TV, and even that could be automatable with home assistant+CEC if that's of interest.
I had a TV once, can't remember the brand, that refused to stream from my dlna server unless it could contact its own corporate servers over the internet first.
In theory, this seems great, but you won't be able to use the majority of streaming applications nor get the same quality out of those applications. Like Netflix, they purposely downgrade the streaming quality on desktop.
Yup.
You generally don't want a smart tv you can hack. You want a decent computer you own sending signal through the external inputs.
The SBC in the TV is, hands down across basically every "smart" TV I've interacted with, a cheap piece of crap (even well into the "expensive" brands and models).
Manufacturers stick the absolute cheapest garbage in there that can output the advertised resolution during playback without stuttering.
So you can spend hours/days/week wrestling this cheap, underpowered board back from the manufacturer... or you can just side-step it entirely and spend much less time and effort sticking a decent computer you own behind the tv.
This!
All my TVs have an Apple TV on them and that's all that is used (aside from a game console here and there). I pretty much never need to interact with the TV OS. Is there a Netflix app on my TV? Probably, I'll never know, I've never even launched the app store.
Unfortunately the family likes live TV, and that is very hard to get without compromising the UX.
OTA TV Tuners fill this niche.
It's been a bit since I've done this (I'm not watching live TV anymore), but something like HDHomeRun worked fine.
It basically pairs an antenna with a small computer to convert to network traffic, then gives you an app on your streaming device to play it back.
You do need to be able to run the vendor's app, and you'll get stuck with that UI for live tv (So yeah - totally agree that you're compromising the UX). But still no reliance on the "smarts" built into the tv.
I have an HDHomeRun box and use it through Plex. I've never installed the HDHomeRun software. Plex immediately recognized it as soon as I plugged it in. There is a noticeable amount of latency between selecting a channel and starting the stream, so channel surfing is pretty cumbersome, but I almost never do that. With the paid version of Plex (Plex Pass), you also get DVR support which automatically removes commercials from the recording, so that's pretty much the only way I use it.