Hello, @marzio.biancardi@gmail.com,
Please see this image: https://postimg.cc/0KyzWMg1 these files need to be deferred/optimized on your site.
Also, it is necessary to use the lightspeed server because Keep the server response time for the main document short because all other requests depend on it.
I can see that you have installed “108” plugins on your site and a total “of 73” are activated please completely deleted the plugins that are not in use no matter whether they are activated or disabled. Try to avoid using third-party plugins as much as possible.
Please delete the unnecessary themes, pages, posts, and products to keep the server clean.
I hope by following the above steps you will start getting the desired results.
Regards 8Themes Team.