Mobile App Revamp & Barcode Tech Integration

I need someone to help me revamp my existing mobile app which i vibe-coded, i think the design is fine but if it's not you can suggest a better design approach. Make sure you test every aspect of the app... (Budget: $3000 - $5000 USD, Jobs: Android, App Design, Backend Development, Database Management, Inventory Management, iOS, iPhone, Mobile App Development, PHP, Supabase)