Web UI design – ’Async Scroll aka Sticky Elements’
Relevant elements always ‘under your fingers’.
An additional CTA conveniently appears at the bottom of the screen when needed.
On a larger screen the product information conveniently 'hovers aside' when the user scrolls through the product's images.
Web-browser's native ‘position:sticky’ feature can be used whenever the product info fits entirely in the viewport, making the scrolling experience even smoother.