@J-3804 Thanks for posting in our Q&A. From your description, did you mean that you want to assign role-based access control to users in distribution list group? If there is anything misunderstanding, feel free to let us know.
If my understanding is correct, it is suggested to check if the group type of the distribution list group synced from Azure AD connect shows "Security" in Groups in Azure AD portal. For example:
In our official article, it shows that all users in the listed Azure security groups have permission to manage the users/devices.
https://learn.microsoft.com/en-us/mem/intune/fundamentals/role-based-access-control#role-assignments
If the group type of the distribution list group shows "Security", it means that we can assign role-based access control to users in this group.
Hope it will help
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