
What is particularly interesting with Lynn is her duality between "battered wife who has to justify the shit her husband does" and "victim-partner in crime". As a character, this would be very interesting if any of them ever faced any consequence for their actions; however, because they don't and all conflicts are resolved in a handwave, it is a duality I find infuriating.
This first paragraph shows Lynn has to rationalize her husband's behavior. She has to convince herself she loves her husband. He is a cheater, he is a pedophile, but first and foremost, he is her husband, so she has to love him, right? She has to stay with him, right? And he is still endearing in the way he is a sperg; he has positive traits, and she likes those traits, so it means she loves him, right?
This is what it reminds me of: a victim of domestic violence who has to convince herself she loves her husband and he loves her to, even if he hits her.

This might sounds nitpicky, but I have a point to make: what time of the day is it for her to throw up both her breakfast and lunch, but also be able to later in the scene leave the school with Cy without getting into trouble for not doing her job? Shouldn't her body already have digested her breakfast?
Weird nitpick of digestion aside, Fanny does not know how to set up a scene. What time of the day is it? Are the corridors empty? Where are all the students, other staff members? All of her scenes feel empty, like she just puts her characters on a white board and never bothers to draw anything around them that is not immediately relevant (which is actually accurate to the way she also draws her scenes, with her characters floating over gradient backgrounds). This makes her world sound flat, dull, hollow. The only things that exist are the things that are convenient to her. This is also the reason why there is so little conflict; she finds those inconvenient to her narrative, because she is a spineless coward who does not want to face conflict, so they do not exist, even when they should.
The lack of description is also apparent with the girl; what does she look like? Outside of her size, her looking like a child, we don't know anything. First of all, her size is compared to Cy, who is a landwhale; anyone looks tiny next to him, so it's not much of an indication. Can we know about her hair color? Is she still wearing clothes? Anything at all?
What about Cy? Fanny focuses on the victim, and while it is mortifying to see a child getting fucked, doesn't Lynn also feel a tremendous amount of dread seeing her husband having sex with said child? The image should haunt her forever, get scarred into her retina like an infected tattoo, but we get nothing. We don't get any description of how she feels, either. We get her reactions – she's shaking, she runs to the bathroom, she throws up. It feels very medical, like Fanny is just writing a grocery list of stuff that happens when you see your pedophilic husband have sex with an underage student.
The most we get is right after Fanny has methodically explained what Lynn does, not what she feels like during the fact, and it still is only a single paragraph.
(also, yes Lynn, your husband is a pedo. I'll let you in on a little secret, Fanny, a writing tip: no one who isn't an "erm ackshually it's not pedophilia it's ephebophilia" Onision-looking predator is going to see much of a difference between having sex with a teenager and a pre-teen.)
(again, this might be very nitpicky and I cannot quite judge myself as I am terrible at the whole this VS that thing, but the "That can't be a teenager, that – that looks like a child" sounds very off to me.)

I know Fanny has a size difference kink, but c'mon. This is the shortest 14 year old anyone has ever seen. This is a dwarf. A hobbit.

Fanny has another issue that is frequently seen with fanfiction writers: she describes things her narrator is not supposed to see. This story is written in third-person limited point of view: we are supposed to see the world through Lynn's eyes. However, Fanny describes her smudged makeup, her bloodshot eyes and bulging veins. The way it is described is matter-of-fact, too, not shown in a way that would tell us Lynn feels the blood boiling in her curled-up fists, her eyes still raw from the pain and anger. We know it's restricted pov since we do not have Cy's exact thoughts, only what Lynn infers he thinks; "he probably figured he should hear". Fanny does this a lot, and for the sake of brievety I will not underline it each and every time, but if I made a drinking game out of it I would get liver damage. The next screenshot is yet another example, but I am getting ahead of myself.
As for the subject matter: why is Cy so confident inviting his students for alone time in his office? Isn't he afraid of getting caught? Is he really fucking stupid? Fanny is trying to sell us this genius sociopath who thinks of everything but then he just... has sex with his student right there, in front of everyone. I find it hard to believe this man spends about 20 years teaching and never gets caught.

Ah, the ultimate fanfiction sin. "she croaks" "Cy mutters" "she growls".
Lynn explodes, and it is the mildest explosion I have ever seen. Me forgetting my fork in the microwave while reheating my pasta the other day was a bigger explosion. And I did not even turn the microwave on. We still get nothing about how Lynn feels, what she thinks. This is meant to be restricted POV, with her as a narrator, but we get so little of her thoughts and feelings it feels like she is not even our narrator, and the narrator is only a stranger witnessing their argument. This makes this scene, which should be very dramatic and tense, fall flat.
Once again, Cy feels strangely stupid and oblivious. In her other works and drawings, she's insisted Cy is intelligent and knows the difference between wrong and right, and simply doesn't care (which is the case for most sociopaths; not the intelligent part, mind you, but most sociopaths do know what is right and what is not, but care very little about following a moral compass). This is part of the reason why Cy does not work; Fanny does not have enough insight on the human psyche to write him properly. He is far closer to the distorted sense of empathy and lack of social awareness autists have than he is to the genius sociopath she sells him as.

Again, like with KAMGO, Fanny does not have any argument as to why it's not a good thing to be having sex with children. Her only argument is always "this is a child!!" and never hey man this is very fucked up you are taking advantage of a vulnerable girl, which is the real argument behind "this is a child". I cannot believe I have to explain this, it almost makes me feel like I am the one trying to make excuses.
The way she writes is so cluttered, too. "he finally says, but Lynn cuts him off", and then she writes Lynn cutting him off. It sounds more like it's the narration that is cutting him off, not Lynn, and because your reader has to spend a few seconds reading your dialogue tag, in the scene they are imagining, there is a beat between the end of his dialogue and the start of Lynn's. To make it flow better, you could say:
Finally, he takes a deep breath in. "I know she looks young-"
"She looks young because she is young!"
Cyrus also comes off as very whiny, like a petulant child throwing a temper tantrum. Which is accurate to a sociopathic narcissist, or a sperg, but not to the image Fanny wants us to have of Cy.
Beloved reader, I am pleased to announce I have reached the 1500 wordcount which earned Kate Anderson an extension in KAMGO. Congratulations if you have made it this far, or my condoleances. This is the homestretch, I promise.

... In which Lynn calms down instantly. She was angry for about two minutes, and then she's better. She's even speaking softly to him, like she's trying to reassure a child who broke a plate that it's ok, it's just a plate. But it was not a plate, it is not a child but your 40 years old pedophilic husband, who you very much caught having sex with his underage student. And Lynn underlines it, she says she feels like she's talking to a teen.

How... how does Cy KICK the steering wheel? How short are his legs? Why would you say "again"? Up until now, he was only using his fists, not his feet. Are you ok, Fanny? Have you ever been inside a car? Do you know what a car looks like? Do you know what leg room is?
Why is Lynn conceding to pedophilia? Why is Cy getting so mad instead of realizing he will never know anyone else who will enable him like Lynn does? Why is Lynn conceding to pedophilia?? What makes 14 worse than 15?? What is this mad world Fanny lives in which this sounds like a reasonable concession and Cy has enough leg room to KICK the steering wheel?

And then Lynn will not do anything about Kate Anderson, who Cy starts having sex with when she is 14. Talk about strong conviction.
Cy is not right about "harm reduction". He could just talk to the girl, explain what he did was fucked up and they should never do this again, and stop it there. It's far better than giving her false hope. Why isn't Lynn realizing this? That the autistic sperg who knows nothing of human psyche (Cy, not Fanny) can't understand this, I can get behind, but Lynn? Who's shown to be the moral high ground?
And hell, why does Cy even care about this girl's feelings? Knowing his wife is onto him and he could get into legal trouble, he should be more than ready to have a plan to let her down quickly and efficiently, without leaving breadcrumbs for the police to find.
The last two lines very much read Millenial/Gen Z writing to me. I would not be surprised to see such a line in Dragon Age:Veilguard.
Well, this analysis is about as long as the fiction itself, I may have gone overboard a bit, but I did try to contain my autism a bit. I do hope you found this entertaining.