If the preview of your notebook cover design is not the only thing you care about, but also getting the cover texture right, this book mockup literally has everything you’re asking for. Anything you put there on the 2 covers, it’s gonna look like hardcovers but at the same time, feel so much like it’s made of soft fabric material all over.
Both of the items in the PSD have ribbon bookmarks too, so if we were you, we wouldn’t just use this mockup for our notebooks. It has what it takes to work as a hardcover book mockup too, as long as it’s a thick book.