looks like we're in the same boat, haha
in order to draw poses from memory, you, of course, have to understand how the muscles and bones of your subject matter move based on their reaction to certain situations, while doing different activities, etc. - something that i have barely practiced in! (eek!) because of that, i'm not the best advisor, but gosh darn it, i'm gonna try my best.
you have gotten better at (1) recognizing the basic shapes that make up the figure and (2) refining said shapes into a more polished figure drawing, which is great! in order to understand how the body works, you have to observe it, which you have been doing by building up your visual library through drawing what you observe. hurrah! now i would say continue to do that, but experiment by constructing the figure out of 3d shapes (cubes, cylinders, you get the gist). i've tried this myself, and although i don't think i'm doing it quite right, it does help me recognize which part of my character is receding into space. and keep watching those art youtubers! most of 'em have more experience and can explain things better than this random girl on the internet!
thanks for reading, and remember to get enough sleep -a mouse who has stayed up past her bedtime