senior WooCommerce performance engineer - Architecture Fix

We are seeking a senior WooCommerce performance engineer to stabilize and optimize a high-traffic store hosted on WP Engine.
The site handles significant Googlebot activity, paid advertising traffic, and is expanding internationally (multi-currency catalogue). The current architecture is not scaling efficiently and requires restructuring before further growth.
Key Issues
Very low cache hit ratio (product and category pages often served dynamically)
Parameterized URLs (_wpnonce, add-to-cart, wishlist, currency parameters) being crawled and breaking cache layers
Excessive admin-ajax and WooCommerce fragment requests
GA4 purchase tracking inconsistencies (transaction_id/value/currency issues)
Performance degradation during traffic spikes
Scope
Full technical audit (hosting stack, CDN/cache rules, theme, plugins, database)
Make product & category pages cacheable for anonymous users while preserving dynamic cart/checkout behavior
Eliminate crawl traps and querystring pollution
Reduce unnecessary AJAX calls and fragment loading
Consolidate GA4 tracking to a clean, single implementation
Improve server stability under load
Provide documentation of changes and scalable architecture recommendations
Acceptance Criteria
High cache hit ratio for catalogue pages
Reduced server CPU usage and admin-ajax calls
Clean GA4 purchase tracking
Stable performance during load testing
This is a performance engineering project — not a design or cosmetic update. Please outline your technical approach and experience with high-traffic WooCommerce environments.