Android App with OTP Login & Subscription

I'm looking for an Android app that uses both Mobile and Email OTP for user authentication. The app should support a subscription-based system, similar to an educational app that sells courses.

Key Features:
- User Login: Both Mobile and Email OTP
- User Profiles with:
- Notification settings
- Subscription based system
- Simple UI: No need for significant design work
- Payment Integration: Use Razorpay or any other UPI payment gateway for subscriptions.

Please note that I only require the source code.