Cross-Platform Video & Voice Calling App (Similar to Friend App)

I am looking for an experienced Flutter or React Native developer to build a cross-platform mobile application for Android and iOS, similar to the Friend App.

The app should have a modern, premium, and smooth user experience with features similar to Friend App, including:

- User registration and login (Phone, Email, or Google)
- User profiles
- One-to-one voice calling
- One-to-one video calling
- In-app coin/wallet system
- Users must purchase coins to make voice or video calls
- Automatic coin deduction during calls
- Secure payment gateway integration
- Call history and coin transaction history
- Push notifications
- Admin panel to manage users, coins, payments, reports, and app settings
- Fast, secure, and scalable backend
- Clean, well-structured, and maintainable code

The app should be inspired by the Friend App in terms of user experience and core functionality, but it should be an original application and not a direct copy.

Please include in your proposal:

- Similar apps you have developed
- Your portfolio
- Recommended technology stack
- Estimated development timeline
- Total project cost
- Post-launch support

I am looking for a skilled developer for a long-term collaboration.