Using Iframes can contribute to slow speeds because an extra request is made to a server.
Also, check all website links (including the most important pages) for any internal redirects (pages that return a 301 status or that display "the document has been moved here" type of messages). Google Page-speed Insights is excellent at finding these. Also, redirect chains are even worse because that's a redirect followed by a redirect, etc.
There is a website that measures how long it takes for a page to process in the background before the first byte is received from the server. Go to:
Place in any URL that you claim is slow and submit it a few times. If the http code returned is anything but 200, then you're in trouble. If after a few checks, your byte speed is at least 0.200 seconds, then its slow and you'll definitely need to look into the entire back end to see if the server as a whole is functioning properly.
Once you get an average number, you can then calculate the waiting time for your webpage.
If the average load time for any item is 0.2 seconds, then on a poorly designed product page, you'll have to wait at least 21.2 seconds for everything to be ready to begin displaying. This excludes the time it takes for the individual elements to finish displaying.
So my advice is this:
Consolidate the small images into a CSS sprite so that you only need to load 1 image file instead of dozens of images.
Combine all scripts together and if they're small enough, include them directly into the HTML instead of calling them externally.
Once that is done, then tune litespeed for optimal settings and make sure nothing else on the server (such as email programs, etc) is slowing the delivery of the webpages.
Unfortunately, one thing you won't be able to control is the number of visitors that visit the site, but if you really want to limit that (just to try to pick up speed somewhat for the moment), you can use a robots text file to instruct various robots on the internet (such as search engine spiders) not to index your pages.