Cross-Platform Marketplace App Customization

Mobile App Developer Needed for White-Label Marketplace App

I have a ready-made white-label marketplace app codebase that needs to be customized and prepared as a production-ready app for both Android and iOS.

Main Tasks
Replace the existing map system with Galli Maps. I am also open to Batoo Maps or another provider if you can recommend a better option for Nepal.
Integrate the eSewa payment gateway for in-app payments.
Add a reliable OTP/SMS verification system for user sign-up and authentication.
Complete the white-label branding, including:
New logo
App colors and theme
App name
Package/bundle IDs
App configurations
Branding in notifications and store listings
Deliverables
Production-ready Android app
Production-ready iOS app
Preferably built from a single Flutter or React Native codebase
Maps, payment, and authentication integration
Source code in a private repository
Clear README and build instructions
Short video walkthrough for project handover
Backend

You can recommend the best backend solution, such as:

Node.js
Firebase
Supabase

Please explain why your recommended stack is suitable for this project.

When Applying, Please Share
Your portfolio or links to apps where you integrated:
Maps
Payment gateways
Marketplace or delivery features
Experience with:
White-label apps
Multi-tenant systems
Your proposed:
Technology stack
Timeline with milestones
Total cost

Shortlisted candidates will be invited to a quick Google Meet to discuss the project and clarify the requirements.

I am ready to start as soon as I find the right developer.