How to remove the Featured Image from the top of the Single Page?

If you want to keep your Featured Image on the Home page but remove it inside Single Post, all you have to do is to add the following CSS snippet on Appearance → Customize→ CSS Editor area and the image will disappear:

.single.single-post .article__featured-image img {
    display: none;
}

If you use Yarpp plugin to display related posts, the CSS you need to use is this one:

.article__featured-image[itemprop=image] { 
   display: none
}