Kotlin Android App Development Existing Fintech Portal

Hello,

I have a complete fintech web portal already developed, live and actively in use.
All backend, admin panel, database and business logic are stable and running in production.

Existing system includes:

* Retailer / Distributor / Master Distributor hierarchy
* Full admin panel and database
* Services already working on web:

* AEPS
* DMT
* BBPS
* Flight Ticket Booking

Requirement:
I want to build a native Android user app to improve smartphone user experience for field users.

Scope of Android App:

* 100% native Android app in Kotlin
* App will consume existing APIs
* No backend work
* No admin panel
* Login via mobile number + OTP
* User dashboard and services screens
* Transaction flow, history and profile
* AEPS biometric integration via RD Service
* App architecture should support future face-auth module

UI/UX:

* Clean, minimal fintech-style UI (Spice Money / PayNearby type)
* Focus on speed, simplicity and usability
* UI can be finalized in 1–2 iterations

Please include in your proposal:

1. Estimated timeline (days/weeks)
2. Realistic and optimized quote (since backend is already complete and live)
3. Confirmation that app will be native Kotlin (not WebView)
4. Relevant experience in fintech / AEPS / biometric apps (if any)

Looking for a long-term technical partner, so please share a practical and honest proposal.

Thanks
Sabir