Your fundamental skills seem to be really polished. Did you do studies to get to that level? And if so, what kinds of studies did you do?
I did many many many many many studies. It’s the whole gamut - anatomy, perspective, color theory, painting, life drawing, observational studies, etc. If you want to draw ‘academically,’ then my best advice is to study drawing cubes and boxes in space. Learn how to rotate 3-dimensional objects in your head and how to visualize said 3D shapes on paper.