Isn't the bigger question where do your Outlook reports go, and what do those reports do? i.e. what does 'directly' mean? If the reports are going to Microsoft, presumably they can filter mails that are going to or via their email servers, or at least adjust their filters. There is no central host that all Thunderbird users use, so I'm not sure how that would work. Perhaps it might be possible to emulate the report for just outlook.com users? I wonder if that could be implemented as an add-on?

Hello As you correctly assume, the SPAM messages are sent directly to the Microsoft servers (this is used to train the Microsoft spam filter). Accordingly, this cannot work with Thunderbird. There are governmental spam offices in many countries. Perhaps a function could be built in to feed these offices (or perhaps simply a field in which you can enter such a reporting office yourself). Example: https://www.report.ncsc.admin.ch/de/chat