I'm not entirely sure what your specific questions are, but the main concern you have obviously relates to the distinction between how Drawabox handles building up organic structures, and how Dynamic Sketching does.

Basically the thing to keep in mind is that Drawabox exists in its own bubble where it pushes specific rules and approaches, but only expects them to be used as part of the exercises we're doing here. These aren't techniques I expect you to use in every single drawing you produce from here on in, and it's certainly not the "right" or "only" way to draw. It is all part of an exercise. Through the act of drawing in this fashion, you're being forced to focus on the relationships between different forms in 3 dimensional space. Being forced to do that over and over, across many drawings, is what gradually rewires the way in which your brain perceives the world in which the things you draw exist. It pushes you from understanding the things you draw as lines and shapes on a flat page, to actually having the exist within a mental model that comprises of all three dimensions.

Drawabox focuses on this specifically because it's what I felt made the difference between myself and some of my peers when I took Dynamic Sketching many years ago. Where I had enough prior experience (having drawn for a decade before then) to make the leaps of logic to understand how even the 2D shapes we were drawing represented 3D forms, some of my classmates did not - and so what they gained from the course was diminished (although still valuable).

What Dynamic Sketching teaches you is how to separate the spatial reasoning skills Drawabox teaches and break them away from all of these hyper-strict rules - the rules we put into place in order to develop those spatial reasoning skills in the first place. With the freedom to jump back and forth from shapes, forms, and even individual lines, it can help us loosen up and ultimately focus more on creating drawings that, frankly, look good.

Circling back to the initial point - Drawabox's rules and techniques are intended only to apply as you work through Drawabox. That, frankly, goes for any course. They do not teach you the right and wrong way to draw things, but rather they give you a set of tools that you can use as you see fit, once you understand how to employ them. There's a whole world out there, and as you embark on your own, you can choose what it is you wish to draw - and the tools at your disposal will help you achieve those goals.

What sets a beginner and an experienced artist apart is not what they draw, but how close what they draw is to what their intent was in the first place.