How to recover deleted calendar events
How do I recover deleted events from my calendar?
Question marked as
The Calendar app does not have a Recently Deleted folder like other apps (Notes, Reminders...). The only way to recover those events would be to restore a calendar backup: Restore your calendars and events on iCloud.com - Apple Support.
Note that this will remove the events entered after the date the backup was made. You may want to screenshot the newer events so that you can re-enter them (or export them; see below).
Alternatively, if you have a Mac, once the backup is restored, you could export the restored events one by one (by dragging them to the Desktop), go back to iCloud.com to restore the latest version of your events and double-click on the saved events on the Desktop to add them to Calendar.