App Code Cleanup and UI/UX Enhancement

I need a comprehensive review and refinement of my app before launch. The app is currently available as source code files only.

Key Requirements:
- Full review of code, design, and launch readiness
- Fix bugs and remove unnecessary code
- Improve UI/UX design for better navigation and user experience
- Ensure robust security for login and user accounts
- Enhance app speed and reliability to prevent crashes

Ideal Skills and Experience:
- Proficiency in app development and code optimization
- Strong background in UI/UX design
- Experience in security protocols for apps
- Ability to improve app performance and reliability

Looking for a thorough, detail-oriented freelancer to make my app launch-ready.