Didn't know they existed. Just called them. They said "no, it cannot be removed".
They suggested signing in with a different account, but when I do that, I get the error message "This account is not allowed to sign in within this network."
Do you get that error if you try using a different account (non-MDM, for example a personal Gmail account) after a factory reset, never using* the MDM account post-reset?
* Feel free to use it in a third party browser such as Firefox or Brave, as another commenter suggested. Just don't use it for an OS login.
From your description it sounds like when your child signed in with the student account, one of the Ok's they hit for GoGuardian put your device on the schools managed account(cps.edu).
If you're powerwashing and it's automatically pulling cps.edu managed policies as soon as it gets online then the school district IT needs to release your device, and then powerwash it and setup again without the cps.edu policies.
Be aware if you want your child to do any official testing or use their student accounts on your personal device the district may require this arrangement.
It is non-trivial to release hardware where the serial number is showing as mated to a managed domain.
If you're power washing and as soon as it connects online it gets cps.edu remote policies you're gonna need district IT to release the serial from management.
My employers have been complaining about skyrocketing health insurance costs since my first job in 1998. This all predates the ACA by at least 20 years.
