Remove featured image on Individual Blog page in Hestia

You might like to remove this image from the Blog Individual page:

Go to Appearance > Customize > Additional CSS section in your WordPress Dashboard. Add the following code:

.single-post .header-filter {
    background-image: none !important;
    background-color: #f1f1f1;

You can change the background color by replacing the hex color code with any other color code of your choice  from here.