Full-Stack Web App with React/Node.js

I need a full-stack web application that integrates both frontend and backend functionalities. The frontend should be built using React.js, and the backend should be powered by Node.js. The application will use MySQL and MongoDB as databases.
Key Features:

User Authentication: Sign-up, login, and password recovery functionalities.

CRUD Operations: Users should be able to create, read, update, and delete data.

API Integration: The app will consume external APIs for additional functionality.

Payment Integration: Implement payment gateway (e.g., PayPal).

Responsive Design: Ensure the application is mobile-friendly.

Real-Time Data Updates: Use WebSockets or other methods to push updates to users in real-time.

Target Audience:
The app is aimed at users looking for a seamless and user-friendly digital experience across desktop and mobile devices.

Timeline:
Please specify your estimated completion time (for example: 4-6 weeks).

Budget:
Provide your expected budget for the project (if applicable).

Additional Requirements:

A clean, scalable, and maintainable codebase.

Documentation for the code and the API.

Testing (unit testing, integration testing).