Problem fixed!!!
Thanks to KDE discussion forums!!
Guess what caused the problem?? 
BLOODY 
CHROMIUM
Normally, I always use Firefox. I don’t even have Chromium installed. Only yesterday I got an AppImage of Ungoogled Chromium to test something out, and apparently they recently had a bug where the browser will corrupt the system font cache or something. Had to run fc-cache -r. 
I open the darn thing once in half a year and it breaks my desktop. You can’t make this up. Google and its consequences truly have been a disaster for the human race. I am not a violent person. However… let’s just leave it at that. :gutkato_ĝengrimacas:
#lang_en #Chromium #Google #KDE #LiGNUx