Hi Khaled Adel, 🙂
Thank you for reaching out!
First and foremost, please check the WordPress prerequisites here:
For better performance and improve security, we obviously recommend PHP 7.3+. Nevertheless, if this is not possible for you (server type, incompatibilities with plugins, etc.), we recommend at least version 5.6.X.
We use WP Engine to host all our demos (https://wpengine.com/). The performance of your website can also be improved, like our demos, by WP Rocket (https://wp-rocket.me/). Finally, we may also recommend Imagify (https://imagify.io/), to shrink your images with lowest quality loss.
You can always add more stuff to improve your page loading time but this is a pretty good start.
Finally, this topic might also catch your attention as one of our user shared the server configuration that has helped him to solve a similar issue:
For all refund requests, please review the Envato Refund policy:
If your issue is matching the described conditions, please introduce your request to Envato. It will be redirected to us.