Angels have the Phone Box
Yeah, unfortunately Edge does not support extensions yet, and it sounds like you may have been served an infected ad (very common these days). Malwarebytes Antimalware Free is not an "active" protection. The paid version probably would have prevented this from happening. Their Anti-Exploit helps in these situations a bit. Also CryptoPrevent.
Solved Scammers Exploit Windows 10 Upgrade Rollout-What You Need to Know - Windows 10 Forums
Hate to see you quit the Insiders program over this!