Develop Comprehensive and Personalized Fitness App

This is a full-stack development of workouts and nutrition plans app tailored to individual needs. For Developer who already have developed similar apps before so same framework can be used to save project cost.
I am looking for an experienced developer to create a comprehensive and personalized fitness app for both iOS and Android platforms. The app should have the following features:

This is a full-stack development of workouts and nutrition plans app tailored to individual needs.
There will guided training showing exercises etc.
Looking for Full-Stack developer with Fitness app development experience.
With personalized goal setting, training and nutrition program
Low budget project
You can use available Open Source libraries (check GitHub etc) to access exercise instructions, photos and videos. It could be avatar or virtual coach showing the exercises.
Some similar related references, I'm looking to build:
https://fitbod.me/
https://madmuscles.com/
https://www.shred.app/

Can be App only with a simple website or functional Website with mobile functionality.
Let me know if you have experience with Fitness apps.
Can you provide Fitness App development example? If not what is closest you have done in the past?
What will be your approach to our project and how do you plan to keep the development cost as low as possible and as fast as possible.
Are you creative developer? Can you implement AI to speed up the development?