without simply stating he is a hack

Because, quite frankly, Graham Hancock is a hack. Even attempting to 'debunk' his fantasies is already giving him undue credence, a seat at the table that he does not deserve. It is a tall order to request someone to devote precious time to wade through the tide of crap that is his mess on Netflix and individually deal with all his points, so I will simply link you to the first of our many recent threads about Hancock, with substantive answers from u/urbanabydos, u/CommodoreCoco, and u/WoolyXBL, plus two more links to previous answers in-thread.

Edit: If you really, really want a summary of why we don't even begin to entertain Hancock's crap, see this twitter thread.