Android & iOS App Build

I need a complete mobile application built from the ground up for both Android and iOS. The core idea and feature set are defined on my side; I now want a developer (or small team) who can translate that vision into a polished, App Store–ready product.

You will handle everything from initial architecture, UI/UX design and coding through to testing, store submission and post-launch support. I’m open to native development (Kotlin + Swift) or a single cross-platform framework such as Flutter or React Native—feel free to propose whichever approach you believe will give the best long-term maintainability and performance.

Please outline:
• The toolchain or framework you recommend and why
• Milestone structure you suggest—from wireframes to final release
• Rough timeframe to reach an MVP and a full public launch

If you have launched apps before, links to live examples will help me evaluate fit.