GTK apps UIs look broken in Debian

What is the problem and how to fix it? gdmap looks like this: I think it has to do with GTK. I'm using Debian 12 with KDE and Wayland. On a nearly identical machine gdmap looks fine. I have libgtk-3-0 and libgtk-4-1 installed and when I enter sudo apt-get install gdmap nothing is asked to be installed and I already tried reinstalling. Other apps like Firefox and Lutris look normal. It's not only gdmap but also other apps, namely VeraCrypt which I installed locally and GParted. The icons can't be seen. LibreOffice is also broken and looks like very old software.