With over eight years of experience in Android development, I am confident in my ability to build the multifaceted app you're seeking. Familiarity with both Flutter and React Native affords me the flexibility and efficiency to navigate between mobile and web app creation. Not only can I fulfill your needs for a functional Android app, but I can also tackle your desktop interface using JavaFX skillfully.
Key components of this project align closely with my expertise. In previous projects, I've successfully implemented user authentication systems, search bars, activity logs, and file metadata features similar to those described. Drawing from this experience, I'm equipped to lend depth and security to your app through approaches like two-factor authentication and access control via user roles.
Additionally, with a background in PHP-based backend development, I assure you that the necessary links to your database will be handled expertly. Importantly, I understand the unique weight file sharing holds in professional contexts. Rest assured that delivering top-notch solutions tailored to your specific use-case is both my goal and my strength. Allow me to create this robust yet simple-to-use Android app for you.