How to set keyboard layout system-wide not just in KDE

Thanks for your reply.
This is my settings in places you mentioned:

Keyboard Settings: English (UK) variant English (UK, Colemak) is selected.

Hardware/Input Devices/Keyboard/Hardware: Generic | Generic 105-key PC

Hardware/Input Devices/Keyboard/Layouts: only gb, English (UK, Colemak) variant is installed and nothing else

TTY layout is still other than Colemak and I can’t type.