Hello, @loiscapirosi,
1- The content you see in this image: https://postimg.cc/wtwvL513 appear on products. To remove it you have to remove the “Full Description” widget from the Theme options >> WooCommerce >> Single Product Builder check the image: https://postimg.cc/t1s0vFrs Now, regarding the price and quantity it works fine check the result here: https://postimg.cc/Tp1Z3V6C
Also, the changes I made in the product backend you see: https://postimg.cc/0zfmXw61 appear fine on the front end: https://postimg.cc/T5JY2rvR
2- I have created a new custom product I set the product price, feature image, and short description as you can see in the image it appears fine there is no issue: https://postimg.cc/f31xYhtV Here is the product URL as well: https://musclepro.com.co/index.php/product/support-testing-product/
Regards 8Themes Team.