A Lesson in Vengeance (Spoiler thread)

Ok. Hear me out. I just finished A Lesson in Vengeance and I am just... unsatisfied?

Particularly related to the ending. Without giving too much away here, I didn’t find it all that big of a thing. A lot of the online reviews talk about this big twist, but it seemed as though Lee was setting up her ending quite early.

Unless I am missing something? I mean, the very last chapter hints at spoiler redemption for the main character (right?) or does her stance with her gf at the edge of the roof suggest that she may be a serial...

Also, it just seemed like everyone was rotten. Right?