Over a year ago, I had made a very similar argument against Homo Deus, from the perspective of a biological scientist.
It was mostly about his misrepresentation of effects when editing the human genome and potentialities arising from that. My thoughts about that:
Genome editing is important today, for many reasons. Agriculture, medicine, environment. But it will be comparatively irrelevant for shaping homo sapiens into homo deus.
However, I came to the conclusion that the real value of Harari’s book Homo deus lies in the fact that we cannot tell for sure in which ways he is obviously wrong. Which makes it an interesting read .
That being said, I agree with you when you claim it is more speculative fiction that people seem to realize. This doesn’t make it wrong per se, but it should adjust our expectations of propability.