Cross-Platform Used Device Tester

I want a single piece of software that can run on both Android smartphones/tablets and iPhones/iPads to verify the condition of second-hand devices before resale. The app must guide the user through a 25-step diagnostic sequence that checks everything from display quality, buttons and cameras to battery health, charging port, Wi-Fi, mobile network, Bluetooth and GPS. At the end it should generate a clear pass/fail report that can be saved, printed or exported as a PDF/CSV.

Core needs
• One code-base or tightly aligned twin apps so the workflow feels identical on Android and iOS.
• Automatic hardware detection where possible; otherwise easy on-screen prompts for manual confirmation.
• Simple start-to-finish wizard that can be completed in a retail environment in under ten minutes.
• Local data storage with an option to sync results to an external system via REST API.
• Clean UI that works on small phones through to large tablets.

I am open to whichever frameworks or languages you prefer (Flutter, React Native, Kotlin/Swift, or other suggestions), provided the final build is stable and easy to update.

When you reply
• Show examples of previous work on mobile diagnostic tools, hardware testing utilities or similar technical apps.
• Briefly outline how you would tackle cross-platform parity and any libraries you would leverage for sensor access.

I will shortlist quickly and move into milestones for prototype, test deployment and final release.