Need Mobile App Developer for Existing iOS & Android App Updates

I have an existing mobile application for both iOS and Android that needs a few updates and fixes. The app is already functional, and I'm looking for a developer to make some UI improvements, resolve a few bugs, and modify existing features... (Budget: $50 - $750 USD, Jobs: Android App Development, API Integration, Automation Debugging, Flutter, Google Firebase, iOS Development, iPhone, Mobile App Development, React Native, UI / User Interface)