I'll just start with the most important part, at least for those who loved Dark Matter. Yes, it is the successor from Blake Crouch that you have been wanting. Not better or worse, they are just too different to make that kind of judgment.

It explores what it would be like if we could enhance humans beyond current limitations in physical and cognitive ability. Unlike the movie which shares the same name as this book, it is not just a straight up high tech Rambo beat 'em up story. The book does have its moments in that regard of course, but it explores much more.

It focuses primarily on the ethics of deploying these genetic enhancements across the board for our species. Showing that no matter how good the intentions are, the unpredictability of the outcome could make for an existential and unintended catastrophe. Though what does that matter if you do nothing with your power to invoke unique and profound change if a different and definite existential risk exists all the same?

I don't quite recall if Dark Matter did have its own moral undertones tucked within in, though Upgrade does and they are quite compelling. It also is grounded in a more near future technological quandary rather than the ever fun theory of infinite universes.

It brings the excitement of the average pop sc-fi book without the shallowness.