Here are instructions for installing the current state of Cosmic https://m.youtube.com/watch?v=3ZCCVRbYYRM

It is in a very pre-alpha state. The promoted demonstrations are being made by people developing Cosmic, so have a deep knowledge of how to configure it manually, or are using features that haven’t been merged into the currently distributed package.

Apparently, some people that work at System76 are daily driving Cosmic, but they must be using a different configuration than what is part of the shipped package. As is, I find it basically a demo that is functional enough to attempt using for more than 5 minutes, but giving up not long after.