It's very clear toward the last 1/4 of this story, the author herself (it's a she I think?) became very tired of the story. The art even suffered in the latest chapters. It's very easy to see the burnout.
A few more chapters, possibly even 1 more volume to level out the pacing, and it would have been perfect.
But when burning out, can't ask for much more than a satisfying conclusion, even if a bit rushed. Which this did.
Thanks for translating the series. It was a fun ride.