@Javier M Thanks for posting in our Q&A.
Automatic MDM enrollment is just configured in "Microsoft Intune", not in "Microsoft Intune Enrollment".
https://learn.microsoft.com/en-us/windows/client-management/azure-ad-and-microsoft-intune-automatic-mdm-enrollment-in-the-new-portal
Honestly, there is no method to enroll existing Azure AD joined device to intune automatically. It is suggested to remove these devices in Azure AD portal and re-enroll them to intune. I have noticed that you want to bulk enroll devices to intune. Hope the following article will help you:
https://learn.microsoft.com/en-us/mem/intune/enrollment/windows-bulk-enroll
Thanks for your understanding.
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