The main thing I want, besides higher performance, is higher resolution to increase readability. Do something like what Apple did when they introduced their ultra high resolution monitors - present it as a standard resolution monitor to software, but then let the OS handle stuff like font rendering at full resolution and overlay it.

That way you don’t cause a performance hit from games rendering more pixels than what’s necessary for a small screen in 3D scenes, but the detail you do need is there to see. They should work with game engine developers and get the OS side support of it upstreamed to the Linux graphics stack (presumably the game mode window manager Gamescope would be the first place to build it into). It would work in parallel to the upscaling algorithm for the rest of the frame buffer.

Stuff like puzzle games and platformers, etc, could even have game engine support for tagging certain assets and object edges and symbols for higher resolution rendering, not just for fonts, so it’s easier to see the important things. You could even do stuff like render faces specifically at higher resolution and do the rest at low res with upscaling.