By optimising WordPress using cPanel Cron Jobs instead of default WP Cron creates reliable, more efficient completion of scheduled tasks and default WordPress functions, which seems to not be great when a website has little to no visitors, or when on a huge site with many visitors. Instructions below:

Add the following code to wp-config.php, right before the /* That’s all, stop editing! Happy blogging. */

// Disabling WP Cron to use cPanel Cron Job instead
define('DISABLE_WP_CRON', true);

Add the following Cron Job into cPanel to be run every 5-15 minutes, replacing USERNAME and PATH-TO to the appropriate values:

/usr/bin/php -q /home/USERNAME/public_html/PATH-TO/wp-cron.php >/dev/null 2>&1