Update: just opted to run the old version using wine which worked. the dark lord may have a problem on the other hand because despite already having a keybinding set, when i press the special action key, it seems that I cannot switch subweapons so I'm stuck with the gun. checking the other classes, it seems the problem only existed with that particular class as of the moment. I doubt that the issue probably had anything to do with the version of GZDoom since I had this issue for the once current version of gzdoom before updating to the particular version that caused the previous bug as well as using version 4.12.