If you are not satisfied with the speed of the Preload feature, you can set the speed of the Preload feature.
The Preload feature works with WP Schedule which works when someone visits your WordPress site. If your site doesn’t receive a lot of traffic, WP Schedule may not work properly so you need to add a cronjon which speeds up the preload feature.
If you call the following url, the preload works manually.
You can set a cron job as below.
wget -O - "http://www.YOUR-URL.com/?action=wpfastestcache&type=preload" >/dev/null 2>&1
Note: The preload option must be enabled.