Custom resolver for remote schema?

We want to wrap the Contentful GraphQL endpoint as a proxy for our site that is used to shape the “Video” type by user/indentity “role”. Effectively to hide the Video.url from non-premium (not logged in users) (Paywalled)

Been reading a lot about “delegateSchema” and “transforms”, however, I think I’m unsure as to if these ONLY deal with the “schema” and not the actual data results.
What we we’re hoping to do was to remove the Video.url from all requests or from the response if the user’s role/identity is not “premium” and the “Video.allowedRole” doesnt match.