[zzhk]

Well, adaptations of exposition-heavy novels will always be tough.
There's simply no feasible way to cram in all the detailed dialogue and monologue.

And as Kadi pointed out earlier, adapting the story faithfully in chronological order of events would make Erica too dominant and set the wrong tone for the series. Perhaps skimming through the origin story was an attempt to address that.

Hopefully the pace will slow down, but if they really are adapting up to Volume 5 in a single cour (12/13 episodes), I really cannot imagine what will result.