So since Qt introduced this very awesome feature of supporting high-DPI displays, any new Qt applications are unusable for me. That is, everything is so huge that barely anything fits on my screen. The issue is apparently that my Samsung screen has useless EDID that makes it recognized as 7" (instead of 32"). I have a DisplaySize override in xorg.conf that apparently doesn't work. I've also tried forcing DPI based on real display size and it only results in font sizes being changed (and not widget sizes). I'd appreciate any tips on how to make Qt usable again because the search engines yield nothing useful. This would be probably something good to be put on the wiki.
For the record, I've been able to resolve the problem by overriding EDID for the screen (see [1] for a guide). However, I'm not convinced all our users will enjoy being dragged through all these hoops to fix the support for their hardware. [1]:https://blogs.gentoo.org/mgorny/2018/09/15/overriding-misreported-screen-dimensions-with-kms-backed-drivers/
I don't really know what we can do in Qt or X11 to fix your monitor reporting a bad EDID. :(