My Sister, the Serial Killer

I picked this one up coz many people were saying that it had a lovely sister dynamic, but I didn't see any of that. All I saw was Ayoola bossing Korede and Korede just blindly obeying her.
Frankly, I was so annoyed throughout most of the book that I almost dnf'ed it, but I kept waiting for something to happen so that I could change my mind but nothing did.
I loved the short chapters coz it was so easy to get thru but I wish the book was longer.
And because the sister was the serial killer, we didn't see most of the action happening, if we had a pov from the sister as well I feel like the book would have been a whole lot better.
We did get flashbacks of the things which happened in the past which led to why Ayoola acted the way she did.
But this book was just NOT for me.
This made me question tho, how far would you go to save someone you love?