I'm liking what disfunctioning potato mentioned, taking some more time isn't a bad idea. In fact just taking a couple of images and studying the body would help a lot to set you up for quicker figure drawing down the road. I'd reccomend studying the skeleton as well as looking out for resources that show the "simplified forms" of the human body. When you understanding what "primitive" shapes make up each part of the body, volume will click and you'll find ways to simplify the body into shapes which you can bring volume too. Similiarly, understanding the primitive shapes and simplified forms of the human body creates structure! (which if you dive into gesture, the combination of gesture and structure is what makes those really dynamic figures). I think you're already understanding a lot of these things based off of your work, insofar as understanding the shapes of the body (and especially through line). if you're not already, look into the "overhand grip", Proko on youtube talks about this in their intro to figure drawing class, and I'm sure Love Life Drawing talks about it too. The overhand grip can change your line quality big time (it also gets your shoulder more active than your wrist which is a good habit to start at your current skill). The fact that you're starting with charcoal says a bit, Im guessing you're already following them! But that's what I got. I love your second image, right most 5 minute sketch, the bend in the figure there looks great!
So yeah, I agree with youur time being too short considering the technique you're practicing here. You're focuusing on contour (it appears that's so, if you aren't attacking with a specific technique in mind then yeah this is contour), where you're focusing on the shape the subject takes up, you're drawing the outside of the figures a lot! Keep going with this at a longer time. But also start lookiing into gesture and loosening thngs up, getting into how the body can be broken down into shapes as well. When breaking down the body you'll improve by understanding where things begin and end, it can further inform proportions will beneft youur contour drawings in the long run too! Gesture and loosing up willl help identify how your figures "feel" as you establish weight and movement with your figures. For now continue with contour, I recommended this to the last person I critiqued but I thnk you could benefit from this as well the artist is good, so considering you're a beginner, they maybe a bit intimidatng. But pay attention to the methods they speak on, specificallly methods 4, 6 & 7.
all in all, keep doing what you're doing! explore those other options soon if you can!
