The Purview Data Use Management Policies feature is currently in preview right now. I have not seen it working yet. I have a couple questions that hopefully someone can answer.
1) If a user has RBAC or ACL permissions set for a storage account will the Purview Data Use Management Policy have precedence or will the RBAC/ACL permissions over-ride the purview policy access permissions.
2) Can a user’s effective permissions ( the cumulative permissions a user has for accessing a storage account ) that were set by applying a Purview Data Use Management Policy be seen through the azure portal storage account IAM.