[vially]

> Do any desktop system handle mixed DPI well?

This works today out-of-the-box in Wayland as long as the applications are Wayland native (e.g.: not being run through XWayland).

[solarkraft]

This is a major pain with the current generation of Electron apps, but luckily the newest version supports Wayland.

HiDPI is also in the works for XWayland, but it looks complicated and still a few months out.