KWin/Debugging - KDE Community Wiki
https://community.kde.org/KWin/DebuggingIn a situation where KGlobalAccel5 is still running but both Plasmashell and KWin have crashed, you can still invoke any keyboard shortcut to run a program that allows you to run a command, such as KRunner, Konsole or Yakuake. With that, you can restart the plasmashell process with: plasmashell --replace
systemd[1133]: Started dbus-:1.2-org.kde.kglobalaccel@0 ...
https://pastebin.com/TBY5kV9n24.06.2019 · kglobalaccel5[1531]: This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem. Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, wayland-xcomposite-egl, wayland-xcomposite-glx, xcb.