Hi,
According to your description, we recommend to post your thread on Microsoft 365 and Office forum. They should have more resources on office 365 Microsoft Defender Advanced Threat Protection, and also should be more familiar with this issue.
Thank you for your understanding.
============================================
If the Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.