Why am I suddenly receiving spam calendar invitations/appointments in Outlook (Microsoft 365 Family).

I am having the same issue, "Spam Calendar Invites" in Outlook 365. The solution I found was to go into Outlook Options and uncheck "Automatically process meeting requests and responses to meeting requests and polls". To get there, do the following:
Mail Icon
File
Options
Mail
Scroll down to Tracking
Un-ckeck "Automatically process meeting requests and responses to meeting requests and polls"

Hope this helps.

I got so excited to see what you found. Then I realized that you may be on the Windows version? I'm on a MacOS version which has been another point of frustration as MSFT seems to have crippled this version in comparison to the Windows version. (Funny that MSFT didn't mention this to me when they were taking my money and pitching the platform compatibility) I don't seem to have the feature you posted about, but still appreciate that somebody is trying to help here. Hopefully somebody with a MacOS version may come up with a similar solution, but I have been through every setting I can find and nothing similar seems to exist.

I am having the same issue, "Spam Calendar Invites" in Outlook 365. The solution I found was to go into Outlook Options and uncheck "Automatically process meeting requests and responses to meeting requests and polls". To get there, do the following:
Mail Icon
File
Options
Mail
Scroll down to Tracking
Un-ckeck "Automatically process meeting requests and responses to meeting requests and polls"

Hope this helps.

Scroll up to my post of Dec. 14 and see the screenshot you suggest. It doesn't work. Many others tried and were disappointed too.

To complicated. Why not just make a right click JUNK icon?

One does not get that option with these calendar events.