How to get data access for a specific user through the REST API

Summary:

Through the REST API, we need to obtain from a given user which BUs are granted and what roles are assigned. We need to retrieve these details depending on the user name that we have. Could you assist me with obtaining data access via the REST API for a certain user?

Content (please ensure you mask any confidential information):

NA

Version (include the version you are using, if applicable):

24C

Code Snippet (add any code snippets that support your topic, if applicable):