Keyboard keys on f5,f6,f7,f8,f9,f10,f11,f12 are not responding for its own specialised functions mentioned ?

keyboard function keys like f5, f6, f7, f8, f9, f10, f11, f12 which is not working, keyboard illuminate down, keyboard illuminate up, Rewind the song, Play/Pause, Forward the song, Mute, Decrease Volume, Increase Volume but there is a software called karbiner elements, through that all shortcut keys options can be customised and controlled properly. Even through Control Center Keyboard brightness and Volume control are working fine but through keys can't be worked. My Question is without that app or control centre those keys are must to be worked?

[Edited by Moderator]