How to configure WP Rocket with Ajax Product Filter
If you have a very big number of products you should use a cache system in order to increase the performance of your website and you can use a plugin like WP Rocket to doing that.
* In WP Rocket set to use the cache for the logged in users, read this WP Rocket post about that. The better solution is to disable the user cache ONLY for administrators, in this way you can see immediate if something changes on your website. Here you find an official plugin to doing that, please visit this page. Thanks.
* Cache the filter url. You can add this argument yith_wcan Here find the instruction to doing that.
Another suggestion is to configure the products correctly. If you have a lot of similar products, is better to create a variable product with X variation instead of X different products. Read this post about that.