Mobile App MVP (iOS + Android)

I need a simple mobile app MVP built and published to iOS and Android. The app is a basic platform where users can sign up/login. One type of user creates an account, uploads photo (s) of the item being shipped and completes the purchase. Another type of user is the driver who picks up the orders. The driver will need back end access to view the route, order, order status, email, etc ( whatever is needed). Plain and simple. The goal is to keep version 1 simple and scalable. The app must be built using Flutter (single codebase for iOS and Android) and use Firebase for the backend (no custom backend). It should include basic features like user authentication, a dashboard, ability to post and browse items, accept items, and a simple profile page. Stripe or Square to process homeowner payments. Calendar or built-in booking to let homeowners request services. I also need help submitting the app to the Apple Itunes and Google Play. I’m looking for a developer who has experience with Flutter + Firebase and has published apps before.