I seem to have an HiDPI issue with Qt apps only, displaying extra large menus and toolbars when system dpi setting is 100+
The easiest solution for this I guess would be forcing a fixed dpi setting for Qt based apps, but I doubt this can be done.
So I think I might use a simple wrapper script for several such apps I have that first (1) reads the current dpi setting and (2) changes it to 96 before starting the app (easy part) and then (3) monitors the dpi setting to keep it while the app is running and (4) changes it back to the original setting as soon as that app is closed. I think step 3 is required in case two or more of such Qt apps are used at the same time.