Comment by klausa
I haven't tried in the last couple of months, but last time I tried connecting Deck to a TV it was _painfully_ obvious it was Linux with a thin veneer of Steam over the top.
Some of that is Valves' to fix, but some other things are just "that's how PC games are" — I genuinely can't believe "render the UI at native screen resolution, but the game at arbitrary different one" is not a standard feature in 2024.
I don't mind my game running at 720p, if I still can view the text and UI at native 4K; but apparently this is just not possible to get on PC.
What you are looking for is a render scale option. It is usually specified as a percentage of your display resolution but could also be combined with upscaling (DLSS, FSR, XeSS, etc.) options.
It's something that is up to the game developer to implement but it is becoming more and more common to see in games now.