So, it appears to be an issue where a few different factors all weigh in at once - QT based apps on High Resolution Display.
I think our clue and direction to follow is in
QT_AUTO_SCREEN_SCALE_FACTOR=
Or
QT_SCREEN_SCALE_FACTOR=
Experimentation may be needed. May need to try different numerical values following the = sign, for example, "QT_SCREEN_SCALE_FACTOR=0.5" or if using multiple screens, "QT_SCREEN_SCALE_FACTOR=0.5;0.5". Maybe "=1.5".
This can be exported from home by including it in
~/.profile
Or placed in the apps exec path.
I am finding this bug listed for Gnome Desktop, but strangely, not for XFCE4. I am not sure if this means that the bug is only present on Gnome or if it has just not been reported as much on other Desktop Environments.