Qt applications display is missing letters and parts of the menus

I’m not sure why but this is happening, no matter what I try(tried changing some settings as you can tell by the ugly background, via qt5c and nothing

)
2020-08-19_14-07
I remember this being a problem on an appimage of a qt application as well.
Is this a qt problem or am I simply missing something?

Could you verify if you have ttf-dejavu installed?

➜  bin pacman -Qs dejavu
local/ttf-dejavu 2.37+18+g9b5d1b2f-2
    Font family based on the Bitstream Vera Fonts with a wider range of
    characters

Yep, they’re installed.

Which DE? Have you set the Qt environment variables and run qt5ct?

Adding to @xircon and putting some of my Manjaro experience to use. As you didn’t reveal any info on your system it is difficult to point in the right direction.

But starting with your .profile

export QT_QPA_PLATFORMTHEME="qt5ct"
export GTK2_RC_FILES="$HOME/.gtkrc-2.0"

Building and installing the qt5-styleplugin from AUR may be helpful as well as the
kvantum-qt5 package from official repo.