Cross-Platform Productivity App Development

I’m ready to bring a new mobile productivity app to life and need a developer (or small team) who can handle the entire build for both iOS and Android. The concept has been validated at a high level; now I want to translate it into a polished, store-ready product... (Budget: min $100000 USD, Jobs: Android, Android App Development, Flutter, iOS Development, iPad, iPhone, Mobile App Development, React Native)