Hello,
Your website performance may suffer from the content you have added to your website. It may happen in case of too many plugins, large not optimized images or other resources. So we suggest you remove unnecessary plugins, install some kind of JS & CSS optimizing plugins like Better WordPress Minify and a caching plugin like WP Super Cache. Also, you can use GTmetrix tool to see what makes your website slow and optimize these parts of your website.
Regarding WooCommerce Cron Jobs, So this is not from Theme and not handled by the Theme, This can be handled by WooCommerce, please read this thread: https://wordpress.org/support/topic/disable-woocommerce-cron-jobs-can-i-run-them-manually/ and try to contact WooCommerce support.
Best Regards.