Ideally you should be able to pull those attributes as defined in the documentation here - https://learn.microsoft.com/en-us/graph/api/user-get?view=graph-rest-1.0&tabs=http
The correct way is to get users using this query and you can check the Mail Attribute- GET https://graph.microsoft.com/v1.0/users/87d349ed-44d7-43e1-9a83-5f2406dee5bd
Share a screenshot of how you are constructing your request and double check the minimum permissions as outlined in the documentation.