Unity actually gives any class with the name GameManager a special gear icon. You cant just forgo the cool gear icon!
(Its not too terrible from an organizational standpoint because most of the scripts are attached to game objects. MonoBehavior is a component of GameObject. For instance, you’d never have player movement in the GameManager class, you would put it in the component class attached to the player character GameObject.)
Its pretty clear that Mark and Micheal Reeves don’t focus as much on design and iteration so much as the ideas behind their creations. The content formula for their videos is different from the other youtube creators you mentioned. If that style of video isn’t your cup of tea, thats ok.
As for the inventions themselves, I have to disagree. I think some of Mark’s creations are fairly well designed, such as the later versions of the glitter bombs.