From my understanding, now that you have intune as the main MDM, you want to use intune and overrid. existing local GPO. Based on your described issue, and during my research i have come across a similar situation here. Additionally, The provided solution successfully resolved these issues for multiple customers.
Refer to : MDMWinsOverGP, This policy is used to ensure that MDM policy wins over GP when policy is configured on MDM channel.
Note:
- In Windows 10 version 1803, this policy doesn't support the Delete command and doesn’t support setting the value to 0 again after it was previously set to 1
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