Earlier quoted context omitted.
Most non-smart 4K screens are more expensive than 4k-smart tv screens though. Really weird, because there's less stuff in it. I just want a nice 50" 4k screen with hdmi and display ports. I don't use all the other junk anyway, since i watch tv via a computer and sounds goes to a surround set.
Is there an equivalent of DDWRT/OpenWRT but for TVs? Most often those are some embedded linux board running some Android fork, shouldn't there be some TV models on the market that are a good hardware/price deal with firmware that can be replaced? Even something that just permanently shows HDMI input with no popup overlays would be good, but AOSP + VLC/Jellyfin would be even nicer.
Get a used mini-pc, install Linux on it, and don't allow the TV to connect to any networks. This is a 50-75 dollar solution. Good if you are on a budget and are not interested in any wiz-bang features like HDR.
There are a few TV-dedicated Linux systems out there, like libreElEC.
Or get a more powerful system with a AMD GPU and install Bazzite on it. That way you get something like "SteamOS for your TV". Pairs nicely with controllers like 8BitDo.
It would be nice to have TVs as open as PCs, but the manufacturers and media companies are ran by dirtbags and would rather have victims then customers.