Hoping you can help me with this as well. I want to do the same thing, but I've already added some code to make the product info sticky on desktop while I scroll. I think it's interfering with your code & pushing my photos down.
https://disc-greyhound-adws.squarespace.com/shop-all/single-anthurium-print
Here's the code I currently to make the info sticky:
.ProductItem-gallery-slides {
@media screen and (min-width: 769px)
{
width: 45vw;
overflow: visible !important;
}
}
.ProductItem-details {
position: -webkit-sticky;
position: sticky;
top: 0;
padding-top: 10vw;
}