App review - privacy

Hi Community,

I'm a developer considering building a health & wellness iOS app and want to verify compliance with Apple's guidelines before investing development time.

BACKGROUND: I want to create an app that helps users understand their health patterns by analyzing various data inputs including screen time and health metrics from HealthKit.

PLANNED APPROACH: The app would use a hybrid ML strategy:

• NEW USERS: Get insights from a generalized ML model trained on anonymized data from existing users (solves cold-start problem)
• AFTER ~30 DAYS: Transition to personalized on-device model trained on the user's own data for better accuracy

DATA HANDLING:

• Users grant DeviceActivity & HealthKit permissions explicitly
• Users select which app categories they want to include
• Optional opt-in to share anonymized data for improving the generalized model
• Transition to fully on-device analysis after sufficient data

QUESTIONS:

• Are there specific restrictions on using DeviceActivity data and sending them to a backend for ML training ?
• Are there specific restrictions on using HealthKit data and sending them to a backend for ML training ?

Any guidance would be greatly appreciated before I proceed!

Thanks!