Switching through groups of calendars using number keys on Desktop is cool but I never really use it because there is no key to bring all of them back up again. This could be as easy as switching the functionality to a toggle: Pressing the "1" key enables or disables the calendar set 1.

Concrete example: Sometimes, I am switching to a monthly view to plan the month with my girlfriend. For this, I want to disable my chores/routines calendar to reduce clutter and bring it back up once I am done planning. Can't quite do that right now using the shortcuts, I have to manually de-select the chores calendar from the dropdown in the top bar and re-select it later.