Hello,

I saw the screenshot you attached. When you enable the sticky add to cart then the scroll to top button is moved up a bit.

If you want to change the position then you need to add the following Custom CSS in the Global Custom CSS area under Theme Settings >> Custom CSS.

.scrollToTop.button-show.woodmart-sticky-btn-shown {
margin-bottom: -18px;
}

You can adjust the value accordingly.

Best Regards.