The exact numbers don't necessarily matter, it's clear that Kaku was a much worse player under Armas. Coaches not named Armas are putting our best player in a position to succeed, and it's clear that Armas wasn't.
Like I said, I do not disagree with the assumption/conclusion. The difference vs performance under Marsch is enough of an indictment, and always was. (I do prefer advanced stats and not just G/A, but the dropoff here is obvious enough for this not to matter too much.)
Just disagreeing with using the performance under Carnell as conclusive evidence of anything, especially after a convenient bump in performance (for the whole team) in the last 2 games. E.g. Barlow's per 90 numbers under Carnell probably look staggering at the moment.