Android Bluetooth App Development

I need an Android-only application that communicates with external hardware over Bluetooth. The core requirement is straightforward: establish a reliable Bluetooth connection from any modern Android phone, then expose a clean interface so I can pair, send, and receive data with the target device... (Budget: $30 - $250 USD, Jobs: Android, Android App Development, Bluetooth, Bluetooth Low Energy (BLE), Java, Kotlin, Mobile App Development, Software Architecture)