Sending, receiving, and organizing email in Outlook.com
If the Spam is being delivered to your Junk folder (not your Inbox) - There is no way to stop it or automatically delete it. This is a long standing complaint from numerous users, myself included.
All I can suggest is that you look at the Answer by "Hornblower409 Apr 23, 2026" in
https://learn.microsoft.com/en-us/answers/questions/5867493/how-to-solve-receiving-a-huge-number-of-spam-email
That Answer has instructions for how to vote for some Feature Request that would give users more control over their Junk folder and some suggestions for MANUAL processes you can use to pick out and Delete any "known" Spam from the Junk folder so you don't have so much to sift thru looking for legitimate emails.
Spam Group Joins
This is a know issue. Microsoft is aware of the problem but there is currently no fix.
For suggestions on how to Leave a Group. See:
https://learn.microsoft.com/en-us/answers/questions/5915544/no-option-to-delete-calendar-group-in-outlook
You can Vote for and Comment on this Feature Request:
Add an option to block being added to Outlook Groups without consent
https://feedbackportal.microsoft.com/feedback/idea/a17de24f-8ce6-f011-92b9-7c1e5244b89c
(You must "Sign In" at the top right of the Feedback page before you can vote).