amazing work such an outstanding work dear Still-life and human-model life drawing. Draw draw draw draw draw loads. You'll get better. Don't be discouraged. My 3d spatial abilities is super crap, and to top it off, I have astigmatism. Just makes it more fun when you're doing life drawing, have a bit of a laugh at how your final result looks a bit distorted and keep it fun. You'll get there! Good luck! i also want to give you some tips on 3d drawing work because im also a painter at my university in fine arts department soHere's my best hot tips:

Don't be afraid of overlaps, not just between two objects but especially between different parts of the same object, e.g. nose and cheek.
Overlaps tend to be more present around the edges of a form.
Be aware that when most people start trying to draw 3D they tend to draw outlines and kind of placeholder symbols for things. Practicing drawing just the overlaps is the thing that will give you that intuitive sense of space. Even if your style is based more on outlines and 2d shapes, having that intuitive sense of space is a huge advantage.
Use construction shapes, contour drawing and all those techniques they suggest in how to draw books. But they are learning tools, stepping stones that you use when you need them.
Practice the techniques that interest you, at your own pace.
Being too focused on improving can weirdly slow down your progress. You'll know you're in the zone when mistakes start to bother you less and you become more focused on the process of solving the problem. The mistakes feel more like 'feedback' guiding you along.
When faced with a challenging drawing, I usually bounce between different approaches until something works.
Drawing is so much more than just 3D space. Weight and movement are probably next on the list; composition, expression, shape language, etc. I think this is why people always go on about persistence, patience and doing things your own way. It's overwhelming otherwise.

good luck dear and again the best post i like it a lot