I think it should’ve ended after the first few chapters

Had the same feeling. At the end, I felt like the author tried to prove a thesis by ignoring any historical happenings that didn't corroborate and stretching the veracity of those that did.

I’m terrified to know there’s a sequel where he theorizes about the future.

I hope that he's better at assessing the future than the past.

Finished "Sapiens" by Yuval Noah Harari and didn't like it at all. Next on the docket is "The Republic of Thieves" by Scott Lynch, really digging the Gentleman Bastard Series.