As an example a shortcut defined with KeyCodeCombination(KeyCode.X, KeyCombination.META_DOWN) reads "Meta + XX" double quotes excluded:
- "Meta" should be the MacOS symbol for shortcut
- the character, here X, should appear only one time
- there's is no space nor + sign

If I compare with an application such as Safari a shortcut is simply the character, either capital letter, digit or any other keyboard key such as [, /, and so on.
For some of them there's a prefix which is the meta symbol, an up arrow for Shift, alt symbol, caret character for control, and so on...

We might have full macos look, IMO, or at least fix duplicated character and use appropriate symbols to represent modifier keys.