Hello, @3D-Active,
As you can check your site speed score in this image: https://postimg.cc/qzftkkKG it is very very low and I mark the things that need to optimize in order to increase your site speed score. Now, by default our theme has a speed optimization wizard feature you can find it by navigating to the Dashboard >> XSTORE >> Theme Options >> Speed Optimization check this article: https://xstore.helpscoutdocs.com/article/100-how-to-speed-up-my-website
Also, You can use a third-party plugin for this like WP Rocket here is an article to know how you can use this plugin with our theme: https://xstore.helpscoutdocs.com/article/128-how-to-improve-wp-rocket-settings-with-xstore
Regards 8Themes Team.