I don’t know what’s changed in KDE since I stopped using it 2-3 years ago, but it’s buttery smooth, and I can actually use it in a Wayland session with NVIDIA (NVIDIA 580xx at that).
The slowness and staggering that it had with my device is no more.
I reinstalled my distro yesterday after running it for about 3 years because some unknown settings had made it become impossible to use virt-manager, so I’ve wanted to reinstall for about a year now.
However, that’s not why I decided to try out KDE again.
The reason is Cinnamon. Since I reinstalled the distro, then installed Cinnamon, for some reason it would just log right back out to SDDM. While searching around, I found a post about how the modsetting driver may be better to use with Cinnamon and KDE, so I decided to use it, but this still didn’t allow me to log into Cinnamon.
So, I just decided that I may as well try KDE, and it works! 
I’m now back to using the best DE known to man. Life is great. 
Thanks to Linux Mint for providing a great alternative to KDE and Gnome. Cinnamon is still a cool DE, the second best, but alas, I can use what I truly prefer again. 
Happy Holidays! 
PS #1: Maybe nothing has really changed (apart from Wayland), and it was me not using the modsetting driver that caused the issue all along. 
PS #2: Like Cinnamon has been for the last 3 or so years, I still won’t be using a full DE for most of the day anyway. For my job, I find that Openbox works best. 
