I think maybe youa re too stuck on details and not paying enough attention to the structure nd proportins. I would recommend staying away from detail completly until the form feels right. When you feel you are getting more of the dynamics of the poses in your drawings, you can start adding more details on top of the structure. Detail such as hair, eyelashes, and outline of the lips will alwas be the least importnt thing in your drawing and if you focus on it when youa re learning, your understanding of form and stucture will not progress the way you want it to.
These drawings have great immediacy and expression. They feel direct and confident in establishing movement and the shading is dynamic. It feels like you are working with light on form and not just coloring in, which is great. I think you are right that you are overthinking the details. The joints and various muscle groups feel overworked and not nessesery correct, making some of the transitions feel odd. I would recommend drawing from anatomy books as an exercise to learn skeletal and muscular structures, so you don't have to think about and are just able to see and record anatomy. Meanwhile just add less detail when you are not sure. Draw what you see when you squint so you don't get caught up in all the little transitions of light and shadow in the anatomy but stick to more major masses you can observe. Squinting simplifies the form and makes it easier to descifer from observation.
