Hello there, I am a recent Linux convert, was using Pop!_OS at first, but since I ended up liking KDE a lot more, I eventually switched to Neon, and it's been more to my liking.
However, I'm encountering a few issues that I can't seem to solve, even with the help of my far more competent and experienced friend, and the main one I'd like som help with today is this:

Syncing Plasma and SDDM; Exactly how does it work, and why?
Simply installing a theme, cursor or color palette from the system settings menu and pressing the "sync" button does absolutely nothing. I managed to get around this by manually installing a set of cursors in the "usr/share/icons" folder, but is there really no simple way of just installing themes and related stuff for all users..?
Since the SDDM greeter has you "logged in" as ROOT before you actually log in with your user account, stuff being installed for the individual user just won't get synced at all, right? Or am I being a total greenhorn and missing something both obvious and important..?

Thank you for your time. I'll probably be posting about the second most pressing issue in the not-so-distant future.