Managing personal Outlook.com account settings, security, and privacy
@Scott Woody said
an increasing number of very likely spam emails in my Outlook365 inbox.
Clarification please. Do you really mean your "Inbox"? Or your "Junk Email" folder?
If the emails are going directly to your "Junk Email" folder, then I'm sorry, but you have no control over emails that are delivered to your "Junk Email" folder. Blocking won't work and Rules don't auto run.
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.
Please advise if these are not in your "Junk Email" folder, and I'll offer some other suggestions.