Android App Screen Size Compatibility Update

I'm looking for a skilled Android app developer who can update my current app to be compatible with multiple screen sizes. The app is currently at Version 1.0 and has some specific features and functionalities that need to be preserved, including user login and authentication.

Requirements:
- Update the app to fit multiple Android phone screen sizes
- Preserve the existing user login and authentication functionalities

Ideal Skills and Experience:
- Prior experience in updating Android apps for screen size compatibility
- Proficiency in Android app development and UI/UX design
- Experience with user login and authentication functionalities

Please provide examples of your previous work and let me know your estimated timeline for completing this project.