Cross-Platform Productivity App Development

I’m ready to bring a new mobile productivity app to life and need a developer (or small team) who can handle the entire build for both iOS and Android. The concept has been validated at a high level; now I want to translate it into a polished, store-ready product.

Here’s what I have in mind:
• A clean, intuitive interface that encourages daily use and keeps friction low.
• Core productivity features such as creating, editing, and reordering tasks; setting reminders or smart notifications; and simple data sync across devices.
• Account creation with basic profile management—ideally via email and one social log-in option.
• A lightweight analytics layer so I can review engagement metrics post-launch.
• Secure, scalable back-end (Firebase, AWS Amplify, or a comparable solution) with user data encryption and privacy best practices.

Deliverables I need to see:
1. UX wireframes → interactive Figma prototype.
2. Fully coded mobile app compiled for iOS (Swift/SwiftUI, React Native, or Flutter) and Android (Kotlin, React Native, or Flutter).
3. API documentation and environment files for easy handoff.
4. TestFlight / closed-track builds, including crash-free verification and device coverage reports.
5. Final App Store & Google Play submissions with compliant store assets.

Acceptance criteria:
• App passes Apple and Google review without major re-submission cycles.
• No blocker or critical bugs in a two-week post-launch warranty period.
• Average load time under two seconds on a moderate 4G connection.

Please include a brief note on your preferred tech stack, any relevant productivity apps you’ve shipped, and an outline of your development timeline from kickoff to store release. I am looking to start as soon as we lock in scope and milestones.