The labels appear when I go over the buttons with the mouse.
Gnome applications (e.g. gnome-calculator) have the same problem.
If I change the application, the buttons will again be blank when I return to the gnome app.
There are menu problems. Some wrong display of gnome-calculator depends on nvidia 470 (I have an old nvidia card, GT640). The system has other problem to display the labels with other application (ArubaSign, a software that signs PDFs’).
ArubaSign works with KDE on Wayland. I tested it with Gnome on X11 and Gnome on Wayland. The problem is X11 in this case (or the couple X11 and nvidia GT640)… It works using my laptop (video card intes + nvidia quadra) with Xfce/X11.