[leppr]

    xrandr --output HDMI-1 --scale 0.75x0.75 --mode 4096x2160

Play with the scale numbers and the resolution until you get the desired effect. Can't give a full tutorial here but "xrandr hdpi" should yield helpful search results.

I'm not denying it's a pain and Windows/MacOS are miles ahead, but this is how you can get by on Linux with X. I use it daily for work and media, on a variety of monitors.

[oefrha]

Thanks for the info, will try this when I get around to it. But this sounds like scaling a low res image to fit the pixels instead of native HiDPI support, is that right? Then it will probably be blurry?

Edit: Maybe you meant using a native 2x scale paired with downscaling. Interesting, sounds promising.