what does the WM Theme: refer to an how & were an what does do the change it to something other then pop if that can be done
My guess would be it’s a GTK theme defined by environmental variable and dconf values.
The GTK dconf values
[org/gnome/desktop/interface]
cursor-theme='Adwaita'
cursor-size=32
enable-animations=false
gtk-theme='HighContrast'
icon-theme='Adwaita'
The gtk config files at ~/.config/gtk-4.0 and ~/.config/gtk-3.0 + ~/.config/gtk-2.0
Should reflect the theme settings too.
[settings]
gtk-theme-name=HighContrast
The QT needs some tweaking too, there is a project that might already be in use
Set up an environmental variable
# Enable QT apps to have gtk theme
QT_QPA_PLATFORMTHEME=gnome
PS I am not a user of popos