I had it gone within two minutes if seeing it appear. Found this thread on it:

https://answers.microsoft.com/en-us/windows/forum/all/how-to-uninstall-copilot-i-dont-want-to-disable-it/b301b77d-b879-4433-9979-f8795805e9f1

The top pinned answer has a single line reg command that I used. I assume there are still pieces of it that will just always be around, but at least it's out of my mind for now.

The GPO method should work similarly, and it's what I'm going to try as soon as I see it start showing up on my work domain. I say when, not if, because these things have a way of getting around our deployment schedules. I just know one day will get a dm from a user asking if its a virus and I'll end up finding out a third of the office already loves it.