WooCommerce Checkout Debugging & Stabilization

We are looking for an experienced WooCommerce agency to diagnose and permanently resolve several intermittent checkout issues on a live florist website. The issues are intermittent and have been reported by multiple customers over time. They are difficult to reproduce consistently, which is why we need someone experienced with WooCommerce debugging rather than simply following a reproduction checklist. Our hosting provider (SiteGround) has already: Verified checkout pages are not being cached. Verified no server-side cache conflicts. Checked ModSecurity/WAF logs. Reviewed PHP/server logs. Confirmed no frontend optimization is currently enabled. Confirmed the checkout currently uses the Divi Checkout module rather than the standard WooCommerce checkout shortcode. Current Issues: Recipient card messages entered during checkout sometimes do not appear in the WooCommerce order. Pickup or Delivery options sometimes disappear depending on the ZIP code entered. Customers are occasionally unable to select dates in the delivery date picker. Entering credit card information sometimes causes the checkout page to refresh unexpectedly. Some orders have reportedly completed without charging the expected delivery fee. Intermittent checkout behavior reported by customers that cannot be consistently reproduced. What we need We are looking for someone to: Perform a complete checkout architecture review. Identify plugin conflicts. Review browser console errors. Review AJAX/network requests during checkout. Review WooCommerce checkout hooks. Review Divi checkout compatibility. Determine whether the Divi Checkout module should be replaced with the standard WooCommerce checkout shortcode. Verify compatibility between all checkout-related plugins. Implement permanent fixes rather than temporary workarounds. Document the root cause(s) for each issue. Required Experience: WooCommerce WordPress plugin development/debugging JavaScript debugging PHP AJAX Payment gateway troubleshooting Divi theme experience WooCommerce checkout customization Proposal Requirements Please include: Similar WooCommerce debugging projects you've completed. Your approach to diagnosing intermittent checkout issues. Whether you recommend keeping the Divi Checkout module or migrating to the native WooCommerce checkout. Estimated hours and timeline.