Maybe it's my prejudice against multiverses and transdimensional travel, but despite the spectacular world building and polished narrative of this absolute unit of a first volume, I never felt this story. There's a soullessness to it that I feel bleeds in from the very concept of knowing for each of these characters there are potentially tens? hundreds? nearly indistinguishable, in the universes next door. If feels underexplained why these specific ones are the ones we follow, why these matter more than all the others, why world changing, one-in-a-million events happen to these, while the others, with one extremely minor exception, don't make an appearance at all.
If it was less hefty I might consider picking up the next one, but as it is this felt to me like too much book for not enough progress. YMMV