Hi @mrctito,
Welcome to the Auth0 Community!
It looks like you are on the right track with using the Management API to get the user’s user_metadata. Specifically, you will want to make a request to the GET /api/v2/users/{id} endpoint.
Looking at your code snippet, I noticed that the exception being thrown in the .client_crendentials command looks to be because the audience is not pointing to your Management API identifier.
It should have the following syntax: https://yourDomain.region.auth0.com/api/v2
Could you please make these corrections and see how it goes for you?
Thanks,
Rueben