Comprehensive E-Commerce App QA

I need a fresh, independent set of eyes on my newly launched e-commerce web app. Your mission is to explore every customer journey, stress the code, and tell me exactly where it breaks, slows down, or puts sensitive data at risk... (Budget: $30 - $250 USD, Jobs: API Testing, JMeter, Regression Testing, Selenium, Software Testing, Test Automation, Testing / QA, Website Testing)