IMAP works in outlook. Its just horrible to set up and half broken. Click "Add account". Then type in your email address, click "Choose provider", select IMAP, then click "Sync directly with IMAP" (dark pattern hidden button). If you don't click that last button, outlook uploads your IMAP email credentials to their own MS Cloud instance, and that proxies all your emails via microsoft's cloud servers. Do they read your email messages for advertising? Nobody knows!

In my testing, the local IMAP client implementation quite frequently launches a DoS attack against your IMAP server. It'll send the same query requesting new mail messages in a tight loop, limited by the round-trip latency. But luckily, almost nobody uses IMAP via outlook because its so difficult to set up.