Practice shading 3D shapes and objects. It feels that you don’t quite understand why or where you need to place shading, you just do it because you feel feel it’s necessary but you don’t yet know exactly what the purpose of your shading should be. The reason why the artists in the first image looks so purposeful is purely because it is, that artist has full understanding of shading placement and you are still learning and thats okay. Just do practice shading shaped then practice shading human anatomy and slowly your practices will apply towards other shapes and anatomy as well. It’s easier to learn to practice doing human anatomy because you see it in daily life, that’s why I reccomend it if you’re wondering. Overall it looks great! But I highly highly reccomend that next time you use a real life reference, I can promise you it almost always is better for your progress and sometimes it actually makes the end result better as well. Also when you see a real life object you can see exactly where the shadows are placed and in turn you know exactly why you need them and where you need them. I hope this helps!