Gym Access Fitness App

I need a fitness app for my gym, accessible on both iOS and Android. The app should allow users to activate a code after payment and gain access to exercises, sets, or timers of their choice. Access should only be available while they are active members of my gym.

Key Requirements:
- User authentication based on gym membership status
- Simple UI to view exercises, sets, and timers
- Code activation and payment integration

Ideal Skills and Experience:
- Experience in developing fitness-related mobile applications
- Proficient in both iOS and Android app development
- Strong background in secure payment integration
- UI/UX design skills for a user-friendly experience

Please provide examples of similar work done and estimated timelines. Thank you!