Custome fields are getting attached to the sticky add to cart, those fields don’t have any functionality to get attached to add to cart button, and because of this problem, it’s taking half more than half of the usable screen space on mobile devices.
I saw the screenshot you attached and visited your website.
As I mentioned in your previous topic that the fields that you are trying to add with the add to cart are conditional fields and without them add to cart is not possible that’s why they are displayed with the sticky add to cart as well.