I would begin by analyzing the current system with performance monitoring tools and reviewing system logs to identify specific bottlenecks. Next, I’d conduct an audit of the legacy code and architecture to understand outdated components that are impacting efficiency. I’d also engage with key stakeholders to gather insights on business priorities and user experience issues. Based on these findings, I’d propose a phased modernization plan—such as refactoring critical modules, considering a move to a microservices architecture, and leveraging cloud solutions—to enhance scalability and performance, starting with a proof-of-concept to validate the approach before full-scale implementation.