I think people are ascribing too much agency to Maya in her relationship with Sensei. She was seven years old, I'm going to need a whole mound of compelling direct evidence before I believe that she was the instigator or driver of a sexual relationship with an adult, and even then the first assumption should be that she was groomed into it. I think, if anything, the scarf story even points against it. It was Sensei that fingered her, all she did was confess her love (again, the love of a seven-year-old).
I don't have an explanation for Noriko's story, but I'm not convinced that it's Maya that she saw. According to the pact they made as kids, Maya can't go to the old district, yet both of them seem to agree that it was Noriko who broke the pact in the present day. If Noriko saw Maya in the old district, surely she would bring that up.
As a side note, I still don't understand what Noriko was supposed to get out of that pact. Even if she was a kid and didn't understand the implications, she must have agreed to it for a reason.
I don't think Maya kissing him in public makes much sense. It's not like the old and new districts are completely separate worlds. If he's at risk of being recognized and unmasked in the old district, that risk would still exist elsewhere in the city even if it's less.
New Maya mentioning the police came across to me as a sex kink thing, since Sensei gets off on how taboo his relationships are. I don't think there was any indication that it was an actual threat or that she had threatened it before.
As this thread's resident Noriko hater, I feel obligated to push back on some of this. To start with, Noriko is not an objective source when it comes to Maya. Her feelings towards her are all kinds of confused, but they include jealousy and bearing a grudge over the past.
More importantly, there's a lot of stuff that Noriko doesn't know about. She doesn't know about Sensei's relationship with Sekai, which was probably a big impetus for why he had to leave the old district. She doesn't know anything about what happened between when he left and when she joined the class. She sees that he's even more broken now than she remembers, so she blames Maya for that, but up until whatever triggered the resets, it seems like he had actually improved significantly outside of having an underage girlfriend.
In context, what she actually blames Maya for is not fixing him, but she doesn't know that the resets made that impossible.
Maya isn't responsible for Sensei ghosting Niki, that happened immediately after the accident when he holed up in his house with Ami. After he started improving and leaving the house, he still chose to avoid her. Even Noriko doesn't blame Maya for him abandoning them the first time.
It's reasonable to argue that Sensei would have eventually let Niki back into his life if Maya didn't push him away, but there isn't any evidence that he was considering it. I think it's telling that Sensei never talked about the Nakayamas with Ami.
As far as I'm concerned, the only thing that Maya was guilty of was pushing Sensei to leave Noriko and the old district behind. Even then, she thinks she had a good reason for it, though I'm sure her selfishness and jealousy played a large part.
It's also worth pointing out that we still have no idea why Maya hates Noriko so much, and Noriko clearly doesn't know either since she thinks it's for loving Sensei, which she realizes makes no sense.
I can't see Maya Prime maintaining this hatred for thousands of years unless either: 1. Noriko has been showing up during resets (and Maya lied about it). or 2. Maya blames her for some aspect of Sensei's present condition.
I'd actually argue that this is the only reason that we have direct evidence for. Sekai and Pareidolia view Sensei being broken as his true self, and they want him to return to that and become the Collector. Maya Prime was pushing him in the opposite direction, trying to get him to care about the girls. When Pareidolia talks about Maya grooming Sensei, he's referring to what she's done during the resets, not to their sexual relationship.