KDE Wayland black screen
But it’s the most sEcuRE black screen ever. Do you see any screen tearing on your black screen? No you don’t. Also, that black screen supports fRAcTioNaL ScaLiNG! That’s the future: black screen computing! It’s also very EnErgY EFfIciEnt! 
AND it has some unique magic touchpad gestures user nobody could possibly live without! 
Yes but that’s an xorg-session log.
Forgive my ignorance but how do you tell what the difference is and what does it mean?
I’m not sure what you are asking? One is an xorg-session.log file and the ither is a wayland-session.log file. 
I had the same problem, I use Nvidia with a relatively old GPU (1050ti).
Updating to 6.0.2 and using Wayland seems to do the trick for now.
I wanted to stay on X11 but a black or alternating brightness screen welcomed me after a lock or sleep. So I will keep using Wayland for now.
Hmmm, interesting. I’m experiencing that with Wayland and Nvidia after updating, not x11; albeit on a brand new system.