That’s right: after you register you can create a new Organization and select “Cloud Manager” for the type.
To answer your question: Cloud Manager is still supported, it’s just that MongoDB Atlas offers a transformationally higher value proposition for users so that’s where the growth is centered and where we’re investing in more and more rich scalability capabilities as well as Atlas Search. Triggers, Realm Mobile Sync, Atlas Data Lake, Online Archive, Multi-Cloud, Multi-Region Charts, etc.
Cheers
-Andrew