Cross-Platform Minimalist Water Level Monitoring App

I'm looking for an experienced mobile app developer to create a user-friendly, visually appealing, cross-platform mobile application for monitoring water levels in storage tanks. This application will connect to a hardware device via Bluetooth Low Energy and or NB-IoT. It will need to retrieve real-time data on water levels and battery status, notify users about critical tank levels, and display historical water usage trends.

Key Features:
- Real-time water level monitoring
- Battery status indication
- Historical water usage trends
- Alerts for various water levels set by user
- Bluetooth and NB-IoT Connectivity Options

Design Style: The preferred design style for the app is simple and minimalistic. The focus should be on usability while maintaining a clean and uncluttered interface.

Ideal Skills and Experience:
- Extensive experience in developing cross-platform mobile applications (both iOS and Android)
- Proficient in Bluetooth Low Energy (BLE) integration
- Strong understanding of simple and minimalistic design principles
- Ability to create user-friendly interfaces
- Experience in developing applications with real-time data monitoring features
- Prior experience with IoT related mobile applications would be a plus.
-Experience with Flutter would be a plus

I am looking for a developer who can deliver a high-quality product that meets these requirements. Please provide examples of similar projects you've completed in your proposal.