WordPress & WooCommerce Developer for UI Fix -- 2

I need an experienced WordPress & WooCommerce developer to fix a UI loading delay issue on my single product pages.
Problem:


Single product page layout does not load instantly


UI appears broken/unstyled for 15–20 seconds


Page becomes normal only after:


Touching the screen


Scrolling


Clicking anywhere




Issue happens mainly on mobile devices


This is affecting user experience and sales


My setup:


WordPress + WooCommerce


Astra theme


Custom CSS added via Code Snippets


Some layout customization on checkout & product pages


What I need fixed:


Product page UI must load instantly on first load


No waiting, no touch/scroll trigger


Fix CSS/JS loading order issues


Remove layout shift (CLS)


Ensure critical CSS loads first


Fix any WooCommerce / theme / plugin conflicts


Solution must be permanent, not a hack


Requirements:


Strong experience with WooCommerce & performance optimization


Understand render-blocking JS, CSS injection issues, and Core Web Vitals


Must test on real mobile devices


Not acceptable:


Reload tricks or timeout hacks


Temporary fixes


Removing features to hide the issue