Looking for an Android developer for long time project

We are looking for someone to continue an existing project (Android), written in Kotlin and the data is stored in firebase.

The app is a coupon, price comparison, cashback application.
We are looking for someone to work via milestones for different tasks.

The application is very complex it has a built in browser, share with normal functionalities, multi language.

A beginner cannot handle the complexity of the project so please do not post if you do not have extended experience with firebase, webview, kotlin.