I would like Feedback on design for calendar view

Dear all,
At the moment within any frappe app, a doctype with some date/datetime input fields can be used to create a calendar view with the _calendar.js add on the doctype file name.

In an organization like a school, it can create a lots of different calendars (one for course schedule, one for your todo/tasks, one for your meetings, one for your assessments, one for your staff/holiday calendar, etc.) This is of course extremely impractical from a user perspective. All these events should be able to be viewed within ONE calendar.

So here is my question(s):
From a design perspective (think here in terms of efficiency on the system / server) should I programmatically create an Event for each of these different doctypes (so everything is readable under one calendar view) ?
Or, and I am not sure if it is possible, should I create sql queries from these different doctypes and return the results to a calendar view doctype. In this case, just reading different doctype from the db and returning the results to one _calendar.js view.

What do you think would be the best way to approach that?

Thanks for your ideas / feedback.