I’m a little late on this but I followed the steps described by @dalto in this post and it worked quite well. I booted to tty, made the switch and booted again to SDDM. NetworkManager needed a restart if I do remember correctly. I swapped most GTK apps like gthumb or lollypop for a KDE counterpart. In addition I created a new user and compared the ~/.config and ~/.local/share with my main account. I made this switch about two months ago and encountered no problem so far (at least I’m not aware of one 
).
1 Like