From Matomo docs: https://matomo.org/docs/site-search/#tracking-no-result-search-keywords
The only way to track the number of search results on the page is to edit the Javascript code, in the search result pages to tell Matomo
how many results are displayed. Once you have this number available in a Javascript variable, you can write:
[...]
var searchCount = 15; // set this value when rendering the search result page
_paq.push(['setCustomUrl', document.URL + '&search_count=' + searchCount]);
_paq.push(['trackPageView']);
[...]
How can I count the number of searches -> searchCount
?