Honestly, Yuri feels out of character here just a bit...
I understand she's clearly jealous that MC chose to hang out with Haru over her, but I think she definitely wouldn't be the type to admit she spread rumors behind his back and have a cold, calculating response to him about how he shouldn't come back to school. I'd imagine she would go and try to scheme into having Haru be removed and to have them bully MC harder and more violently so he'd fall back to her as his only pillar of support. She's not the kind that is outwardly or intentionally malignant to him, but instead tries to justify her actions by saying that she knows best for him and that it's all for the greater good. (Which, in her mind, would not only be protecting him from potential abuse, but to allow herself to get what she wants, which she thinks is inherently just.)
Yuri definitely would be a lover scorned, don't get me wrong, and she would definitely feel hurt, and then would frame herself as the victim, but I don't think she would outright try to harm Miura when she thinks she can probably still have him as her own. Remember that the reason she wants Miura is because everyone's told her she can't have him because of his lower social standing, and I got the sense she really pitied him in sense. It's strange...
Hopefully we get a chapter from her prospective?