Oh you know I could never let this go untouched.
Firstly I will say: It is possible she was never meant to he redeemed, and that is not the defense that people think it is. That is an admission of either deep ignorance or repulsive malignance on behalf of the writers.
Next I will say: No plotline for a show with a child audience that involves an abused child being abandoned by the hero to the manipulation of the villains and then *blamed for the results of being manipulated by her abusers* can ever be considered well written. I invite anyone who disagrees to take time and reflect on exactly what that entails. If they still disagree I invite them to never interact with either a child, child media, or any form of child service ever again in their life. Such people are menaces.
Now to tackle the specific flaws with *this* plotline from a purely narrative standpoint even if it were merely a part of a larger arc:
It actually begins in Despair Bear. Prior to this episode Chloé was the classic mean rich girl archetype. You could do anything with that. This episode reveals her abandonment issues for the first time. With this door open she is initially humanized and one key to why she is the way she is has been provided. This was the first loan on her arc. As I said, prior to this the writers had no narrative debt to pay off. They used this loan to play for emotion so it needs to be repayed later. That is how narrative works.
Style Queen/Queen Wasp are the episodes they truly mortgage the narrative though. They introduce Audrey and she is openly verbally abusive on screen. *At this point I personally feel you are committed, you do not let any child abuse go unpunished* My personal bias aside, it builds on despair bear. We see the damage being caused in realtime. We see she has no protection at home from Andre. This doesn't mean she is suddenly a good guy in the narrative but it means she is now a child in need of help. In a child's show that takes precedence over any other role she may have. Her public display is a clear desperate bid for approval after being dumped on in realtime.
Her train-incident is a 'Gwen Stacy's spine' moment. As in, there is no reason she should not have been able to stop the train. Ladybug and Cat Noir stop the train using a three inch pipe and Cat Noir's staff braced on nothing special. There is zero damage. IE- physics were *only* applied to Chloé just like they were only ever applied to Gwen Stacy's spine in Spiderman. This undercuts the narrative they wanted to use this act for. If anything having Chloé engage in some Fury-style antics would have worked better.
The end of Queen Wasp is the point of no return. Having seen firsthand how Audrey treats Chloé, Marinette still sticks her nose in trying to reconcile them. When Audrey can't even bring herself to say she loves Chloé without choking on the word, Marinette highlights all of Chloé's *worst* habits as a means to getting Audrey to finally pay attention to her and see her as someone worthwhile(for five minutes at least) Reuniting a child with an abuser and doing it by highlighting all of the behaviors that are *bad* is a horrible thing to do. *This is not a knock on Marinette.* It is a valid mistake for her to make as a protagonist. However once she *does* the narrative has made the commitment to her learning and correcting her mistake in the future. This never happens in ML.
As Panda stated above, giving Chloe the miraculous again was a dangerous proposition. Marinette had a good intent but it set things up for the villains to attack Chloé, the person Ladybug had chosen to put in the way. As the protagonist and team leader Marinette has a narrative obligation to anyone she utilizes for her team. That's how leadership works.
Hawkmoth tries to bribe Chloé and she rejects him. Mayura tries to bribe Chloé and she rejects *her*. This is more than any other temp hero has been subjected to at this point. The narrative beat is clearly her 'taking her first steps'. There is yet more narrative debt. It is all piling up to a clear arc, deviating from that arc requires paying a wicked exchange rate. It's like borrowing from a bank and trying to pay them back in goats. It might work but you're going to need to make it *really* worth their while.
The first missed beat is that despite it being clear Chloé is both targeted and does not understand why she needs to be sidelined, Ladybug does nothing. The leader fails to protect one of her team. Again I must state- This is not damning Marinette. It is a mistake a character can make as long as the *narrative* treats it as a mistake and a tragedy (spoiler:it doesn't)
Just for icing, Chloé has a literal Bee signal. People always lament 'If only there had been some sign!' The girl was flashing it into the sky! They didn't need to show her doong that but they did! Doing so means it's one more thing added to that narrative debt. It's one more excuse the protagonist doesn't have for not acting.
And despite abandoning Chloé it does nothing to help her or her parents(why would it?) Hawkmoth still targets them. The villains disable the signal. (Sabrina is conveniently absent) We get to see Marinette distracted by her jealousy of Kagami leading to her not transforming back *and then we see her gut instinct being to pick Chloé before she is shown thinking of Adrien and Kagami together and letting jealousy get in the way again!*
At this point you've put *so* much on Marinette's shoulders. She has made relentless errors as a protagonist and leader. The narrative debt looks like the US debt. This could all lead to a pay off though, it is still feasible!(Spoiler: it doesn't)
With Miracle Box in hand and heroes already distracted while Mayura's moth batters Fu the villains decide to rope Chloé in because ????????. No seriously, there was zero need for this. They had just windfalled all the miraculous. They could all three whup on Fu, bugger off, and horde the prize. There was zero reason to give a single Miraculous to a child from a rational standpoint. The *only* reason is that Gabe figured he had tormented/isolated the emotionally abused child to a point where she would be a wreck of an akuma.
If this is the narrative reason then it's blatantly acknowledging the abuse setting up for that big payoff mentioned.
But the fight goes down, and we're left with Chloé desperately trying to reclaim an aluma to have any control left in her life. That fails, she gets a talking to like that will stop Hawkmoth from doing the exact same thing tomorrow. Everyone else gets a happy ending *even the parents whose petty fighting started this finalé are laughing and lovey and ignoring her completely because haha dumb evil Chloé*
Zero payoff. Inverse payoff. The opposite of payoff. Laugh at the girl whose torment is the focus of all this while her shitty parents go bone in city hall. Gross.
Nothing about this as it was written can be considered good because it did not pay off.
It *might* have had a chance if they had stuck with the framing *the show itself does* during master Fu's voiceover that says 'Some lose hope' (said while Chloé us using the bee signal to reach out to Ladybug) but nope. It isn't presented as tragic, it's presented as 'evil bad Chloé, laugh' in the end.
S4 and onward just keeps this framing. Despite her initially welcoming a sister she had no reason to care about(until she felt Zoé had betrayed her) despite Chloé being manipulated by the girl who Manipulates *everyone*(Lila) despite Gabriel and Tomoé manipulating her again, despite Chloé's gut reaction *still* being to arrest Monarch, Despite her mother never once showing her affection and openly mocking her again, despite her father *blaming everything bad he's done on her*, none of it is framed as anything but 'Chloé is bad'.
And the end result of a father abandoning the chold he failed to raise properly so he can steal his not-daughter and leaving her with her abusive mother *who is shown cutting in the moment they are alone* is framed as 'justice'.
There is no place outside of the most depraved circles of fiction this can be considered anything like a satisfying narrative arc *especially in a show aimed at children*. 'It's the child's fault the father fucked them up?' seriously? That is 'well written'?
This arc is the narrative equivilent of someone borrowing several grand from you over several years, then when time finally comes to pay they say 'What money? And try to gaslight you into thinking the loans never existed and you are a bad person for thinking they did.