Fixing disappearing icons and freezing on KDE plasma

KDE Plasma is officially the buggiest, slowest and most impractical desktop environment for Arch! Why did I use it, it looked nice, and since I actually do work on my computer instead of doing distro reviews I never tried anything else since I didn't have time to install (and configure) a new desktop environment.
Here's how to make it slightly less unusable.

[@Dahen2]

thanks for warning me, will this be fixed in the future?