Two jobs ago, I had written something for this; but it was written at work, so I wasn't able to keep it. Also, it was on premises Exhange, not Microsoft's cloud. But I recall, the exchange IMAP server isn't too horrible, although a bit slow. Perl with one of the CPAN IMAP modules, plus a little bit of caching, and I could do all sorts of filters that couldn't be done in Exchange (like sorting read mail into archive folders).