Resolve WooCommerce performance / plugin conflicts / MySQL query issues

Hi guys! I need a VERY skilled provider who can sufficiently diagnose, repair, and improve the performance of a new (soon to be launched) WooCommerce website. The successful provider must be able to diagnose issues and resolve problems with SQL queries (remove duplicate queries, reduce requests, etc), locate/fix plugin conflicts, and (ideally) be able to adjust MySQL server config settings. Some PHP/JavaScript customization could be needed if plugin conflicts exist. The main issue we're experiencing is when customers add products to the cart. If they are not logged in (shopping as guest), the performance is "okay" (not great, but "okay"). However, when a visitor logs in, the cart gets VERY slow. For example, adding a single product may take anywhere from 15 to 25 seconds, and the more products that are added to the cart, the longer it takes to add/edit/view/checkout (I've witnessed add to cart times as high as 45 to 50 seconds. Yikes!). My client uses a variety of plugins from major vendors (Woo, YITH, etc.) -- mostly related to shopping cart rules (retail/wholesale, tier pricing, bulk discounts, etc.), and they offer FedEx, UPS, DHL and USPS as shipping methods. I believe the shipping calculations are something to look at too because the performance somewhat improves when the shipping plugins are disabled (especially FedEx). This certainly doesn't solve the problem, but it does reduce the add to cart time to around 8 to 12 seconds. We've tried many different plugins that integrate with those major shipping providers -- and performance issues exist with all of them, so my best guess is there are duplicate queries and perhaps plugin conflicts somewhere else in the platform. Your job will be to inspect the website code, analyze queries, isolate the functions (and plugins) which are causing the issues, repair (or rewrite) these functions as needed, and resolve most (or all) of the major MySQL query bottlenecks. Being able to properly optimize MySQL server is a big plus. - This website is hosted on a dedicated server. - This project needs to be completed in a timely manner. - Low reviews / negative reviews / etc. will not be considered. - I can provide more information as needed. Just ask! Thanks!