I think I have identified the bug now. The breeze package (was upgraded, see above) changed the wallpaper file types from jpg to png. Now the default config of sddm/sddm-theme-breeze does not find it, as it wants a jpg in the file theme.conf . Please fix theme.conf in package sddm-theme-breeze from
background=/usr/share/wallpapers/Next/contents/images/5120x2880.jpg to background=/usr/share/wallpapers/Next/contents/images/5120x2880.png The controls, e.g., shutdown et al. are not visible as they are drawn white on default background white (this is a sperarate bug, if you are asking me). Maybe this could be more smart and detect such a border case.
