You might want to check out MailTrigger (https://www.mailtrigger.net/) — it's a programmable SMTP server that can even call an LLM before sending emails, so everything you listed is technically doable: blacklists/whitelists, phishing detection, spam rollups, virus scans, link previews, etc. It’s not directly related to the MS email stack, but if you're self-hosting and looking for a flexible, programmable layer in front of your mail server, it could be a good fit. It’s still under development (though already running in production for my own company and a few early adopters), and the pricing page is just a placeholder for now. But the docs are public, and I believe it can cover what you're aiming for.

One thing to note: while the website mainly talks about multi-channel notifications, MailTrigger is actually more like IFTTT or Zapier, but specialized for email — when a message arrives, it can trigger smart, programmable actions. You can turn your existing email system into an IFTTT-style automation engine. It supports JS and WASM for preprocessing and routing, so you could, for example, auto-reply with an LLM-generated joke or handle customer support queries dynamically. The website might not fully reflect this yet, but the docs are more complete and show what’s possible.