When readjusting everything from font size 12 to 10, one type of applications just ignore this. And that is the Qt applications.
So, when starting KeePassXC, font looked quite large compared to everything else, so I had to readjust in the VM used.
example of how it looks before change:
Starting the program to make the changes:
[user@personal ~]$ qt5c
Change the font to 10 and resize your app.
It looks quite the same, when having the same width, but if you compare the font in the title, you can see the difference.