I cannot reproduce the issue on three machines. All are running GNOME, two with Wayland sessions.
If you did not already know, Manjaro is based on Arch. Most packages including gtk4 are synced directly from Arch.
If you can reproduce the issue on Arch, feel free to submit a gtk4bug report. However, I doubt Arch will add the MR as a patch–especially if they can’t reproduce it.
Then we’ll have to wait. It’s possible upstream will tag it before GNOME 47.1 in a few weeks. We’ll see.
Nope. I can reproduce it on Gnome and Sway with only GTK4 Applications on Wayland. Actually, when I switch the cursor theme to Adwaita (default), it scales correctly. So xcursor-breeze actually results in:
(gnome-system-monitor:7764): Gdk-WARNING **: 10:57:51.343: ../gtk/gdk/wayland/gdkcursor-wayland.c:210 cursor image size (64) not an integer multiple of theme size (24)
So in my understanding it is the theme that needs to be updated, to be compatible with wayland. The cursor size here is 64px and the default size is set to 24px at dconf. So the image size is 64px and wayland requires here the half. So set it to 32px and it looks good. No more warnings.