is there any way for a developer who has access to the Firebase console to be restricted access to the real-time database, preventing them from reading and writing any data directly?
When you add a collaborator to the Users and permissions panel of the Firebase console, you can set what permissions they have. The defaults are Owner, Editor, and Viewer, with the latter granting read-only access to all (Firebase and Cloud) products in the console.
You can also choose Assign Firebase role(s), in which case you can select per Firebase product what permission the user has. In this case you can exclude them from having access to the Firebase Realtime Database.