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…
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.