I have tried COSMIC, but it came across as rather buggy to me, so I couldn't continue to use it, other than finding nothing compelling to make me want to use it. I do understand that it is a young project still. All of the desktop environments that are essentially offshoots of Gnome (Cinnamon, Budgie, COSMIC, MATE) seem like attempts to make Gnome more usable. Call me a dyed-in-wool Plasma fan, but they just don't do it for me.
Having said that, going through system settings in Plasma vs. Gnome-based often seems silly to me:
* Plasma - make change, then 'Apply' the change
* Gnome - just make the change, no extra step!