In my case, the issue is fixed by simply installing xdg-desktop-portal-gnome. > sudo zypper in xdg-desktop-portal-gnome (Solution found in https://www.linuxsurge.com/2021/10/how-to-fix-uglyjagged-fonts-flatpak-gtk.html) I'll wait the other user to confirm this solutions and we can mark this bug as closed I think.