Hi,
Thanks for posting your question in the Microsoft Q&A forum.
I have a question that I'd like to confirm with you, does 'Exchange side' refer to EAC or Outlook?
It is not possible to delete quarantined emails in Exchange admin Center or Outlook.
1.If you want to delete or release quarantined emails, as the administrator you can manage the quarantined emails in Microsoft Defender under Email & Collaboration -> Review.
- If your quarantine policy has quarantine notifications set up, end users can receive a notification email informing them that an email has been quarantined, and usually providing a link to access the quarantine directly. However, emails cannot be deleted, only released or blocked.
- Administrators can track emails whether they are quarantined or not via Message trace. Based on the mail conditions, mail trace is performed in Mail flow->message trace in EAC.
If my answer is helpful to you, please mark it as the answer so that other users can refer to it. Thank you for your support and understanding.