I just had a client ask me for something very similar! Google around I found this post, and thought I would share my solution... It was not manageable to add hundreds of product blocks and the summary block doesn't contain the item-id needed to link it to an Add to Cart button. It was best to use the product list page. I figured out a solution that works great on desktop and mobile.
https://www.bradgood.net/articles/how-to-add-an-add-to-cart-button-to-a-squarespace-product-list-page
