Set the number of search results per page

I try in vain to set the number of search results. I know that I can set the number of “posts” per page in the wordpress settings. I once entered 16, but would like 20 anyway, but the latter fails completely.
Then in Elementor I used Woocommerce’s product widget for the search results output. Here I can specify that the products found should be shown in 4 columns and 4 rows. So 16.
If you search for “tee”, you get 214 results. On the first page 12 products are shown and only on the following 16 products are shown. Above the search result on the first page it says “Results 1-16 of 214”, although only 12 are shown.

First Search result page with 12 results
URL

Second searchresult page with 16 results
URL

There seems to be another factor that influences the display of the number of search results. Can anyone help me?

WordPress 6.1.1
Elementor v3.11.2
Elementor Pro v3.11.1
WooCommerce version 7.4.0

The page I need help with: [log in to see the link]