Mobile Competitive Trivia Game

I'm seeking an experienced game coder to develop an android competitive trivia game. Please provide evidence of your past work. The game should have the following features:

Quiz format
Multiplayer capability
Leaderboards
Integrated wallet
Convenient wallet top-up via mobile money
High-quality and well-organized code
Simple integration of new quizzes
Easy maintenance

Initially, we will begin with a few features. However, I would like to know if you can incorporate new features and deliver quickly.