not really, a lot of that could be table driven rather than hard coded, allowing for DM customization. And where that fails, the DM can still deactivate / override it
you quite literally are not seeing this, they simply have not shown the DM side yet
As to a 4 month old DNDShorts video, I have no reason whatsoever to believe that he is correct in that, you on the other than insist that he cannot be wrong.
Just in case you were unfamiliar with the term