Best way to save keyboard shortcut config to disk?

I couldn’t find any way to save in PropertyStorage nor couldn’t find a enum in SettingID
So I have two questions

I’m planning to make a class derived from PropertyStorage, and implement the way to save keyboard shortcuts to disk. Is this correct?

Is it difficult to add an enum, something like “keyShortcuts”, in SettingID?

You can’t add to an enum I’m afraid.
However, you probably want to implement your own actual storage within the PropertyStorage interface (similar to how ApplicationSettings in tracktion_PropertyStorage.cpp is defined and used) which you can then use to store settings of your own.

I will do as you say.