How to delete iPad calendar events when no edit option appears
Solution 1:
Go to Settings app → Passwords and Accounts and scroll down.
The subscribed calendars should be there and click it and click delete account and you should be good.
Solution 2:
If you don't have the ability to delete the event (it's a shared calendar) then the Edit button will not appear.
For such events, you should remove the shared calendar through Calendars at the bottom of the app, then choose ⓘ on the shared calendar and select Delete Calendar.