Two-Sided Marketplace Mobile App Development

I need real offers made so i can compare .

I'm looking for an experienced developer/team to build a two-sided marketplace app where people post tasks/jobs and service providers bid to complete them — similar to Airtasker( photo attached)

Core features needed:

User signup/login + profiles (Client & Provider roles)
ID verification
Post a task (description, budget, location, photos)
Browse/search tasks with filters & map view
Bidding/quoting system
In-app chat
Secure payments with escrow + platform commission
Ratings & reviews
Admin dashboard
Push notifications
Platforms: iOS, Android, and Web (admin panel)

To quote accurately, please tell me:

Your experience building marketplace/on-demand apps (examples/portfolio)
Recommended tech stack (native vs Flutter/React Native)
Estimated timeline & milestones
What's included (design? app store submission? post-launch support?)
Ongoing maintenance/hosting cost after launch
Please respond with your quote and relevant experience.
I have no model or any date ready so everything will be done by the developer.
Please quote me with the average cost to build the whole app and lunching in store.