Federated authentication of google workspace with apple business manager

Hi Team, I am testing federated authentication of Google Workspace with Apple Business Manager (ABM). After successfully configuring the Google Workspace domain in the ABM admin account and syncing it, we attempted to enroll a device using automated device enrollment and login with the Google Workspace account as the managed Apple ID. However, during enrollment, the system asked to create a new user, even though the username was replicated from the Google account, and prompted to enter a new password.

Could someone please explain why this is happening? and aiming to enable a seamless login without user creation or password generation.