Probably not the solution everybody wants, but I would say for the sake of not complicating things for the developer, local shortcuts are necessary and global are a bonus.
If you need global shortcuts for any app, use the macOS built in shortcut feature in the settings. Or get a more sophisticated third party app like fe. BetterTouchTool for this.
No ne for every app to do this by themselves.
@MaxVonMustermann are there shortcuts for start last used task?