Cross-Platform Transportation Management App (update features)

I am building an enterprise-grade transportation application that must run seamlessly on iOS, Android, and the web. The project calls for a robust front-end in Flutter or React Native—whichever you can justify for optimal code sharing—paired with a scalable Node.js back-end... (Budget: $250 - $750 AUD, Jobs: AngularJS, API Development, Flutter, JavaScript, Mobile App Development, Node.js, PostgreSQL, React Native)