OS: Fedora 36
Font: Windows Tahoma
Problem: Qt6 applications seemingly do not use my fontconfig settings (which are used for everything else, including XFCE, GTK2/3/4 and Qt3/4/5 applications, and web browsers).
strace -e file and
$HOME/.config/fontconfig/fonts.conf is indeed being read but it's not seemingly used correctly.
I do not see any error messages in console from Qt6 applications.
I have a suspicion something in terms of fonts support in Qt6 has changed drastically but I haven't been able to find anything.
Here's how Qt5 applications look like.
Here's how Qt6 applications look like.
I've filed a bug report because I haven't been able to find anything relevant.