Hardware E-Commerce App QA Testing

My hardware-material e-commerce mobile app is approaching its launch window and I need a fresh, systematic review of every shopper action. The focus is pure functionality: cart behaviour, checkout flow,... (Budget: ₹12500 - ₹37500 INR, Jobs: Android, Mobile App Testing, Software Testing, Test Automation, Test Plan Writing, Test Strategy Writing, Testing / QA, Usability Testing)