If still the filters do not show up:

4. copy and paste the following code into the functions.php file of your current theme:

add_filter ('yith_wcan_use_wp_the_query_object', '__return_true');

and go through steps 2 and 3 once again.

The ability to filter products in stores today is a necessity to make the search for goods more efficient. Users are accustomed to using this tool, and not offering it can hurt your store. If the above methods do not work, then move on to using a custom search plugin that will give you smart filters as well.

How to fix the Woocommerce Search and Filter not Working issue using ExpertRec

The main purpose of the smart plugin is to improve the user search experience for any WordPress based website. You can manage a lot of settings provided by the plugin to customize its appearance by selecting what fields to display and changing styling options. It’s pretty easy to select the required fields to be used for the search in the plugin settings.

Add Search to your WordPress Website