source: building it right now for our app. supports sharing, organizations, and role hierachy (viewers, editors, admins).
With my friend, we are building https://foundryapp.co. It's a tool that helps developers build their backend much faster. We offer prebuilt templates for specific backend functionality that we deploy onto your app's backend.
Would you mind sharing more about what are the exact struggles when implementing subscription management?
If you don't want to share it here, feel free to send me a DM or email me. The email address and my twitter handle are in my bio.