The login credentials you posted does not work. Please check. I checked a product archive page and a single product page the actual size that are used is around 700 x 500 px. If you're in a 4k retina, that might be a bit pixelated or blurry. Please check your settings in Appearance > Customize > WooCommerce > Product Images and increase the size of the Main image width and the Thumbnail width close to your original image size.
WooCommerce by the way now automatically regenerates the thumbnails. But, if you don't see the effect, try using the third party regenerate plugin.