A large e-commerce platform is experiencing performance issues during peak traffic hours. The platform uses microservices, containerization, and a cloud infrastructure. You have been tasked with identifying and addressing the performance bottlenecks. Outline a comprehensive approach including: 1) diagnostic methodology, 2) potential bottlenecks to investigate, 3) short-term mitigation strategies, 4) long-term architectural improvements, and 5) monitoring strategy to prevent future issues. Consider resource constraints and business requirements.