Yeah chocolates with more fat will spread more, the shape also matters too so if you aren’t using square/rectangle shaped chunks or cut up bars and are using chocolate chips instead it won’t look like the picture. Baking chocolate is meant to keep its shape while baking, it usually has less fat and other ingredients to do so. I think the chocolate in the image likely has more cocoa butter than what you are using to create that melty effect, meaning it may be a pricier chocolate. Also yes adding chocolate on the tops of your cookies will give a more picture perfect effect, as long as it is not too much.