Hello,
What permissions are needed for the User Account?
The account must be assigned the Global Administrator or both the User Administrator and Exchange Administrator roles in Microsoft Entra. Unfortunately, there is no possibility to be more granular about permissions in case of a user account.
Can we restrict permissions more with a User Account instead of an Application Account?
With all the limitations Microsoft are introducing for their APIs, it is highly recommended to use an application account. Also, it is very likely that user accounts will be decommissioned for such connections.