Correct, you are running at least two separate GraphQL APIs.
If you look at the architecture of modern tech companies they are already moving in this direction. Facebook has TAO for data access, and twitter has Strato: https://about.sourcegraph.com/graphql/graphql-at-twitter/ The purpose of these data services is to enable feature developers to focus on their feature instead of worrying about infrastructure, caching and scalability. Prisma is an open source version of that same pattern.
To the question of whether you should expose your database API to other internal services or not. This very much depends on the kind of architecture you are choosing. If you are building microservices you typically want to ensure that only the microservice owning the data can access and update it.
Facebook has a quite different approach where TAO enforces access control policies, and all services can query the same data. We'll explore how Prisma can support this pattern in the future.