Here is how you can disconnect a student’s Google sign-in from the unwanted teacher account:
💡 If you disconnect Google but don't delete the teacher account, the account may relink when the student signs in again. (This is because the student’s Google email address usually matches the one on the unwanted teacher account.) So please be sure to include that final deletion step. If the student is linked with their actual parent or teacher's account, using a different email address, this is unnecessary.