There are many best methods to identify and delete duplicate items in Outlook Calendar efficiently. I can suggest the best way, like
SameTools PST Duplicate Remover, and delete duplicate items in the Outlook calendar. The software automatically finds duplicate items like emails, contacts, notes, calendar, tasks, events, etc, in the Outlook and deletes them without losing important information or data. The software handles a large number of duplicate Outlook items without any glitches. The software is capatible with all Windows OS and Outlook versions. The software has an easy interface for non-technical users, and they can try the free demo version.
Visit here:
https://www.sametools.com/duplicate/pst/