Interactive Learning Quiz App Development

I'm looking for a developer who can create an engaging and interactive mobile app for both iOS and Android. This app will allow guests to purchase and participate in two microlearning courses, complete with a variety of multimedia elements and playful questions.

Key Features:
- Guest access without the need for registration or login.
- Payment gateway for course access.
- a choice of different microlearning courses in hospitalty. I need the set-up, as I will write and create the content for the course myself.
- Course content to include: videos, interactive quizzes, images, multiple choice questions, and connect-the-words exercises, set in correct priority, ...
- Automatic email delivery of a course completion certificate.

Ideal Skills:
- Cross-platform mobile app development (iOS and Android)
- E-learning software development
- Integrating multimedia content into apps
- Implementing a secure payment gateway
- Knowledge of user experience design for gamification elements

Please provide examples of similar projects you've completed. Looking forward to your bids!
All is based on my website: www.overdeliver.be