Cross-Platform Rating App Development

I'm seeking an experienced mobile app developer to create a simple and clean rating service app for both iOS and Android. The app will facilitate anonymous ratings among multiple user types: brands, customers, and solution providers.

Key Features:
- Must support 10,000 users daily
- Multi-user Logins: Brands (A), Customers (B), and Solution Providers (C) with comprehensive profiles including images, videos, bios, and achievements.
- Anonymous Rating System: B rates A & C; C rates A only.
- Point System: B earns points for daily actions, incentivizing engagement.
- Notification Alerts: Remind B to rate A & C daily/weekly.
- Real-time Leaderboard: Rankings for A & C based on anonymous ratings, sortable by city, state, and country.

Ideal Skills & Experience:
- Proficient in developing cross-platform mobile applications.
- Experience with user authentication and profile management.
- Strong UI/UX design skills for a clean, simple interface.
- Knowledge in implementing real-time data and notification systems.
- Familiarity with rating systems and leaderboards.

Please provide examples of similar work done and an estimated timeline.