I need a woocommerce expert who can review and suggest improvements to our website esp for issue related to downtime/slow website

Ou website slows down or is not available for seconds;the cached pages load quickly but the uncached pages do not at times; the current developer generally mentions the reason as plugin clashes but the downtime happens even when the plugins are uninstalled; we need a person who is an expert in woocmmerce and can help review the causes for the downtime