[clircle]

I like MATE, but it (and most other DEs) doesn't have HiDPI support. So, back to Gnome.

[robgibbons]

I use MATE with HiDPI on my XPS 15 and a 4k Dell monitor.

Look at the MATE Tweaks tool and you'll find the option.

[renewedrebecca]

MATE definitely supports HiDPI, although I don't think it tries very hard to auto-detect it. (But I'm running a 1440p monitor. 4k might be better.)

[dangerbird2]

I've found cinnamon has the best HiDPI support, especially when you need different fractional scaling factors for multiple monitors and can't use a Wayland-based DE because of your GPU drivers (looking at you, NVidia)