.NET E-Commerce Backend Optimization

Our live e-commerce site is built on the Microsoft .NET stack and, while feature-complete, the backend has begun to drag under load. Pages that once rendered in under a second now spike past five, occasional time-outs appear in the logs, and CPU usage sits uncomfortably high... (Budget: ₹1500 - ₹12500 INR, Jobs: .NET, .NET Core, ASP.NET, ASP.NET MVC, C# Programming, IIS, Microsoft SQL Server, Performance Tuning)