Is there anything we can do on the performance?

The plugin uses standard WP_Query php class of WordPress for creating filter requests. So sometimes filter works slowly on some hostings. I can advise some things in this case:

  • use cache plugins, for example this one
  • switch off dynamic recount in the filter
  • use Autoptimize
  • add more memory to your wp site
  • use PHP 7.2 (or higher) - it is faster (250%) than PHP 5.6 and eats less memory