You have one job to diagnose and then fix why my website has so much lag. I have two hosting companies, it scores okay on speedcheck sites like pingdom and google, though seem to have lots of https requests.
I have WP Fastest Cache, so dont think just need to use one
Site for testing is [login to view URL] this site does not have ssl it is just for testing main site has ssl. this site do not respond until you have looked at the site and can tell me the time it takes for homepage, shop page and shopping cart page etc to load.