You've got some great studies and can carve shapes quite well.
I think this latest study is showing progression, but I think it either doesn't go far enough or goes too far - depending on what you are wanting to do.
If your goal is to push toward realism (which I think you are), you need to lose your lineart under the shading or maybe adjust opacity so it is much lighter. The lineart is fighting against your rendering efforts and makes everything feel muddy and cluttered. Afterall, the point of lineart is to describe form without shading and when you add that shading the lineart needs to shifted. It might have a different feel if you were using color though...
Or if you were to lean into the style in your lineart and use comic-style cell-shading, leaving the stark transition, I think it would make your lineart really kick ass.
