Something changed in the gtk3 stack.....
Error shown when running systemsettings5 and adjusting gtk config:
(systemsettings5:10320): GLib-GIO-ERROR **: 17:44:21.187: Settings schema 'org.gnome.desktop.interface' is not installed
Seems gsettings-desktop-schemas is now a hard depend in gtk stack, not sure which package changed, but opera has shown this issue for almost 3 weeks now (thus it has not been updated in the [apps] repo, new versions have stayed in [build] because of this).
No option now but to add gsettings-desktop-schemas a hard depend for kde-gtk-config and opera.
You can test by installing the just added gsettings-desktop-schema package:
sudo pacman -U http://kaosx.tk/repo/build/gsettings-desktop-schemas-3.28.0-1-x86_64.pkg.tar.xz
EDIT:
Seems plasma is more and more intend to require full gnome to actually work 🙁
This commit now sets this new depend for kde-config-gtk:
https://github.com/KDE/kde-gtk-config/commit/87040960da7e9e587b4cb61251807e164aa53483
This patch will be reverted for KaOS, so gsettings won't be needed.
EDIT 2:
Rebuild kde-gtk-config is up, no longer needing gsettings:
sudo pacman -U http://kaosx.tk/repo/build/kde-gtk-config-5.13.4-3-x86_64.pkg.tar.xz