Hello,
Page speed depends on
1. host provider
2. optimized content and images
Please check your pages on the default theme.
Also, try to increase the size of your product images by using lossless image compression and resizing images.
You will have to upload images of equal sizes and proportions, in addition, you need to set the equal title length.
Also, check after deactivating your third-party plugins which are not required by the theme.
If you have any questions please feel free to contact us.
Best Regards.