Cognitive Services with `authorization_code` request.

When trying to create a token for use in an immersive reader, it's an option to use a client_credentials grant type. This, however, is not my preferred method. I want to grant delegated access to a authorization_code request from Microsoft SSO. The issue is that using the scope https://cognitiveservices.azure.com/.default is not allowed when using other (specific) scopes. There are no docs for any scopes on cognitive services, nor are there any options in App Registrations to add the scope. I know https://cognitiveservices.azure.com/.default is a valid scope because it works in Postman. If anyone knows the scopes, please tell me 🙏. Note, it doesn't seem to work without specifying a tenant.