Good day. 

I have a field called "Event date". Based on that date I want to schedule activities x amount of days before or after that event date.

example I want to schedule an activity to check if moneys have been paid 14 days before the event date. Can this be done without the intervention of the likes of Zapier?

i.e. Date of Activity = "Event Date" -14days

Or I want to create an activity to send a Post Event Survey 3 weeks after the event date hence:
Activity Date = "Event Date" +21days