What is the best way to organize a microservice architecture with multiple user groups?

Question

JSON Web Token

At the moment, there is an API Gateway and an authorization service associated with the Users database, which stores all user data. Requests to other services are made through middleware that checks the token and returns the user's role, if this user is allowed to perform operations on this API route, then everything is OK.
There was a problem with scalability, since each role has its own data, which is nevertheless stored in the same mongo db collection. What is the best way to refactor architecture and separate user groups? Do I need to make separate microservices for them?