Hi there, if removing or turning off rules in Outlook 365 doesn't solve the issue of emails being sent to the Trash folder, consider these steps:

Check Server-Side Rules: Use the Outlook web app to inspect for any hidden rules.
Review Junk Email Settings: Check your Junk Email settings in both the Outlook client and the Outlook web app to ensure they are not too aggressive and to see if the senders are mistakenly marked as junk.
Disable Focused Inbox: Outlook 365 has a feature called Focused Inbox that sorts your emails into two tabs - Focused and Other. Ensure that this sorting is not causing the confusion. If needed, you can turn off Focused Inbox from the View tab in Outlook settings.
Inspect Additional Filtering or Sweeping Rules: In the Outlook web app, there's a feature called "Sweep" that can automate how emails from specific senders are managed. Ensure no Sweep rules are inadvertently affecting your emails.
Evaluate Third-Party Add-Ins: Run Outlook in Safe Mode to see if add-ins are causing the issue.
Contact Microsoft Support: If issues persist, seek assistance from Microsoft Support.