Of all the things that add to … or take away… from your style, is the package (physique) that you bring with you.
Take for example the five (5) pitchers below. They all have unique styles with some similarity - but individually, each to their own. And as would be expected, each has a pitch inventory with strengths and weaknesses, endurance and tolerances, that follow suit.
Now remember, we’re talking about the human condition here. A condition that does not remain the same or with any degree of finite detail over and over again during repetitive motion. However, professionals in any sport have dedicated their lives to closing the gap of variation, and if they intend on surviving, they’d better keep that gap as narrow as possible.
Now here’s the big question that goes well beyond “who has the right form and better body motion(s)?” Do you want to sacrifice a large portion of your life, giving up your social experience of those around you, neglecting even the most basic of interactions with those you know to perfect the same degree of performance as those in this game that you admire?
In any event, to address your comments directly about a pitcher’s form and progressive motion - to the end, there is no one source of chapter and verse that suit all comers. Again, we as humans aren’t so adaptable to uniform movements where one size fits all. Nor do we have the mental capacity to fix our attention spans in such a neat and orderly fashion.
Good question though.