It would be nice to be able to managed Realm Applications via Terraform, similar to how MongoDB Atlas can currently be managed via the mongodb_atlas from Terraform provider.
I agree. Example: Triggers. Triggers can be created with the Atlas Terraform Provider but take inputs from the Realm side in app_id and config_service_id. Per MongoDB Support, these would require a Realm Provider and until then must be manually gathered and input into the Trigger resource, making for a clunky user experience.