Review the following code for performance, effectiveness, and efficiency. Also check for:
- Query leakage or unnecessarily loaded data
- Code readability, styling consistency, and mature coding practices
- Adequate and clear inline comments
- Code replication and DRY (Don't Repeat Yourself) violations
- Proper error handling and use of async/await
- Potential security vulnerabilities
- Outlier detection and data inconsistencies
- Next-step recommendations for improvements or refactoring

Please suggest specific fixes and enhancements with clear reasoning.