If you haven't read RandomRex6's Danganronpa V3 fanfiction titled Three-Point Shot, I would advise you to get out from under that rock you're clearly living under and go to Archive Of Our Own or Fanfiction.net and read it. I promise, it will be well worth your time. Now, with that said, I'm going to tell you all something that this fanfiction really did right.
That something is HaruMaki's character development. Her character arc, both in canon and in TPS, is about her realizing that she is still a human no matter what she did in the past. If I had to be honest with you, I'd say that TPS does her arc more justice than the game does. Don't believe me? Here's why.
Her character development involved more than just the training trio (especially Momota). Hell, there isn't even a training trio because Akamatsu is alive in this fic. But what I'm trying to say is, her character development didn't just happen because of Momota. Yes, the Fitness Club (which is what I'm calling Akamatsu, HaruMaki, Momota, and Saihara) all helped her in that regard. And then there was that conversation she had with Yumeno after Chabashira was executed, the one where she said that it wasn't bad to kill bad people. If HaruMaki was truly a compassionless monster, she never would have even cared to notice that Yumeno was having trouble coping in the first place.
There was also the time where all of Saihara's secrets were revealed and he fell into a depressive slump. If HaruMaki was a compassionless monster, she never would have informed the Fitness Club about Saihara's clinical depression, and she would never have told them not to treat him differently because of his depression or his bisexuality. This proved that she really cared about him.
And then...hoo boy...there was Momota's funeral. During that excruciatingly despairful scene, HaruMaki spoke only the truth about how much Momota meant to her. If she were really a compassionless monster, she never would have broken down crying as she said what she said.
In conclusion, this fanfic really does HaruMaki's character the justice it deserves.