- Figure out how to set up 1 global hotkey in your chosen desktop environment,
- Assign to it some simple dummy target ommand. Which you know always works. And is easily verified
That will ensure you can check and test that a specific hotkey assignment is actually definately working independantly of the specific desired action. This is important because the desktop environment can also occupy pre-configured 'system keys' and if they are already being mapped to something other default system wide actions then (likely) will silently be ignored.
So being independant here from the subsequent specific desired target actions in some special app or whatever. Which themselves definately might have other own different issues or not behave correctly. And especially when being invoked from the compositor via this method (rather than a logged in user terminal etc.)