I got the same problem with any desktop i try to install:
[kaos keos]# LANG=C pacman -S manjaro-budgie-settings manjaro-settings-manager papirus-maia-icon-theme warning: manjaro-settings-manager-0.5.6-2 is up to date -- reinstalling warning: papirus-maia-icon-theme-20181011-1 is up to date -- reinstalling resolving dependencies... looking for conflicting packages... :: manjaro-budgie-settings and manjaro-xfce-gtk3-settings are in conflict (manjaro-desktop-settings). Remove manjaro-xfce-gtk3-settings? [y/N]
I tried gnome kde and many others ... what is wrong with xfce gtk3 here?
Thank you very much for ...