Hello Andrea,
Thank you for reaching out and I am happy to assist you with this.
I’ve checked your website and as I can see the W3 Total Cache is enabled on your website:
<!--
Performance optimized by W3 Total Cache. Learn more: https://www.boldgrid.com/w3-total-cache/
Object Caching 805/809 objects using memcached
Page Caching using memcached{w3tc_pagecache_reject_reason}
Lazy Loading
Minified using memcached
Database Caching 3/69 queries in 0.058 seconds using memcached
Served from: calabria7.it @ 2022-09-16 17:59:00 by W3 Total Cache
-->
Can you please share the screenshot of your admin area and see if you have W3 Total Cache under Plugins>Installed Plugins and if the Performance is listed in the left admin tab?
Thanks!