To
stop duplicate emails in Outlook, click the Delete button. The folders will automatically be removed from the Deleted Items folder if they're in the Deleted Items folder. In addition, you can set the automatic send and receive every time you receive an email. To get rid of the email messages that you don't need, delete the old messages manually. To do this, you need to know how to access the Deleted Items folder in Outlook.
See also -
https://emailspedia.com/how-to-recover-deleted-emails-in-outlook/