Shopify Speed Optimization Expert Needed

We are looking for an experienced Shopify developer to diagnose and fix a sudden performance issue that appeared overnight on our e-commerce website. Issue: - Product pages load visually, but key interactive elements are extremely delayed. - Size Guide drop down, calendar selection, size selection, variant pickers, and other clickable elements can take several minutes before becoming responsive. - The issue began suddenly and was not present previously. - Homepage and other pages appear to load, but product page functionality is severely impacted. What We Need: - Immediate troubleshooting and diagnosis - Identification of any app, script, theme, JavaScript, or third-party conflict causing the delay - Performance optimization and implementation of a fix - Explanation of root cause and recommendations to prevent recurrence Additional Opportunity: While resolving the urgent issue is our immediate priority, we are also interested in identifying broader opportunities to improve site performance, speed, user experience, conversion rates, and overall storefront optimization. If additional improvements are recommended beyond the immediate fix, we are open to implementing them as part of this project or a continued engagement.