>>5932264>how wide and how long the torso isYou'll get some intuitive sense of that after copying references for a while.
>how it behaves in 3d space>i made i circled in red the areas i'm having difficulty withYou could solve those issues by taking écorchés and slowly copying them, slow enough so that you can understand every square inch of the form.
You've got the basic form okayish, but that's the easy part.
FWIW, try looking at Proko's videos on YouTube too, and copy, copy, copy until it's carved into your brain. It'll then be much easier to invent & stuff.