Shopify Custom Product Page Build

My Shopify store needs a purpose-built product page that goes beyond the default theme blocks and works flawlessly in production. I want one template that I can easily assign to any product inside the Shopify admin, with every element wired up to my existing catalogue, cart, and checkout... (Budget: ₹600 - ₹1500 INR, Jobs: CSS, HTML, Inventory Management, JavaScript, JSON, Shopify, Shopify Development, Web Development)