Hello,
I have checked your product page, and the Sticky Product option is working correctly.
When the sticky option is enabled, the product description section remains sticky while scrolling. If the description section is taller than the product images, the images section will remain fixed instead.
In your current product layout, the sticky functionality is already active. However, if you would like to see the sticky effect more clearly, please go to Theme Settings > Single Product > Gallery and change the Gallery Grid layout. After changing the gallery layout, you should be able to see the sticky behavior while scrolling the product page.
Here is the Sticky Product Example:
https://woodmart.xtemos.com/shop/furniture/reflect-chest-of-drawers//?opt=product_sticky
Best Regards