Full Stack Developer (Flutter/Native) - Pharmacy E-commerce with Uber Direct Integration

We are a growing medium-sized pharmacy chain looking to develop a custom mobile e-commerce application. Our goal is to bridge the gap between our physical stores and digital convenience. The project will be hosted on Google Cloud Platform (GCP), leveraging cloud computing for scalability and performance.

Key Features to be Developed:
- Barcode Scanning Checkout: A feature allowing customers to scan product barcodes inside our physical stores, add them to a virtual cart, and pay directly via the app.
- Geolocation & Inventory: A real-time "Store Finder" that shows the nearest pharmacy branches with available stock based on the user's current GPS location.
- Logistics Integration: Seamless integration with Uber Direct for rapid home delivery.
- Real-time Sync: Integration with our internal ERP/Inventory system to sync prices, stock levels, and active promotions in real-time.
- Personalization: Integration with Google Search/Ads API to display products based on customer interests and search history.
- Payments: Integration with third-party payment gateways (local Brazilian gateways).

Technical Stack:
- Frontend: Flutter (iOS & Android) and Native approach for more security in some pages, like on the checkout, chart....
- Backend: PHP (Laravel or Slim preferred) & Python (for data processing/integration).
Infrastructure: Google Cloud Platform (GCP).

What we are looking for:
- Proven experience in e-commerce mobile app development.
- Experience with Google Maps API and Geolocation services.
- Experience connecting apps to legacy ERP systems via APIs.
- Strong understanding of security and cloud infrastructure.

PS: Give us 3 estimates:
1 - If you're going to do only the Frontend
2 - If you're going to do only the Backend
3 - If you're going to do Front and Backend