Could you allow the user to limit calendar visibility on a category-by-category basis?
I have Agenda categories for home, work, and school. In Apple Calendar I also have calendars for home, work, and school… and bills, birthdays, holidays, and others. When working within school notes in Agenda, the only calendar of interest to me is my school calendar. Currently they all display. There are so many calendar entries to scroll through and most have nothing to do with school.
It would help to minimize clutter if we could narrow calendar visibility at the category level. Not a pressing concern. Perhaps a someday feature.