Oof, the anti-yuri comments and the "I don't trust this Gyaru, bitch be scheming" from the author all strike me as unfair.
I like this new character's whole "gyaru who skips class but still gets #2 rank, and is smart and caring and a good teacher" concept. She seems very earnest and serious/focused/discerning in her own way. She does what's actually necessary (and does it very well and seriously), and doesn't do what's not actually necessary, and this optimization lets her do more of what she wants to do, and her attentive/discerning nature also makes her, among other things, a good teacher.
Her attitudes of "I'll do it myself" and/or "Authority doesn't always know what's best (so I can skip class and study on my own to ace the tests)", her deflecting ("tsundere") response on page 17, and her actions of making-money-where-she-can all suggest that she's overcome a challenging and unaffectionate childhood and is trying to maximize her own independence and power to keep from reliving that, but again, she's still attentive as a teacher and shows concern for Wataya, so she didn't let her childhood make her TOO cold.
In conclusion, she's very mature (but still a bit overly emotionally guarded but I'm sure she has reasons) and has a very strong spirit and mind, and all naysayers are just haters who don't respect the hustle and the vision.
(Addendum: I also think she has some notable overlap with Fuji as far as embracing "Playing the Villain", which I think puts her on the "good guys" side in context of the story, so I'll be pretty surprised if she DOES fuck over anyone we care about. Even for money. So far what we've seen her take money for are "Selling good cat videos to a guy who likes cat videos, plus feeding the cats and probably recording videos of them herself" and "Selling good tutoring to a girl who needs good tutoring". Give the people what they want, but never work for free. Doesn't mean she fucks people over. Teach is probably a cheapskate lol.)