Flutter Chat App Development Like WhatsApp

I'm seeking an experienced flutter mobile app developer to create a chat application akin to WhatsApp. This app needs to be compatible with both iOS and Android platforms.

We want Admin area to monitor chats, Web Version & Mobile App

We already have purchased 2 Chat App from Codecanyon (You can choose the one which matches requirements)
1. Chatzy
2. Chatify

Following tasks are involved
1. Logo Updates - Splash Screen, App Icon & Logo
2. Change Login functionality (Slighly not much)
3. Installing Web & Admin Part on the Development Server
4. Disabling Video Call Option (We wanted to keep Voice Call Option)
5. Testing if Send Message, Reply, Forward, Delete, Emoji, Attachment, Voice Note, Location, Status, Broadcast, Voice Call, Add to Contact, Specially Groups features are working properly.
6. Uploading App on Android & Apple Store

Milestone is for the Fix Budget. Once the Phase I (above mentioned) finished we will create another milestone with additional requirements.

Ideal Skills:
- Proficiency in Flutter mobile app development.
- Prior experience in developing chat applications will be a significant plus.
- Strong understanding of implementing voice and video call features in an app.
- Ability to create a user-friendly interface for media sharing.

I am open to discussing your ideas and suggestions for improving this project.