I don't think the lack of coherency is a problem I think it's part of the experience of being an obsolete meat machine that is getting a direct injection of the future right into your brain. If you feel slightly confused about the rushed pace of the story good because that's how everyone else is feeling experiencing it, it's a wild ride, you're not entirely sure what's going on but it sure is simulating.

Also another relation, I see qntm's RA as a more recent rewrite of this story but with a rather different ending.

I also always interpreted the beginning of the book as deliberately written to make the reader feel the future shock that Manfred is trying to stay ahead of.