We can’t log in to your new site, but while testing we see the next things that are independent of the theme – https://gyazo.com/2afbf1f5a7aa66e48744c80e285d9c3d https://gyazo.com/e547e35573bfda3bcb7a525e22fda9e8
Have you read articles about DOM? Every additional element on the page increases the DOM structure. To reduce it remove the elements, there is no other way, unfortunately (for example limit the number of products in the slider, or remove some elements etc).
If you are not satisfied with the theme speed we could only give you a refund.
One standard license is valid only for 1 project. Running multiple projects on a single license is a copyright violation.