So, au where Chloe actually gets a proper redemption and, while still Chloe, is a good person. Adrienette is happening, and Chloe and Kagami start going out once they figure out they have feelings for each other and get over both being disasters who don't know how to deal with their emotions. Marinette starts inviting them to go on double dates with her and Adrien (something she hasn't even invited DJWifi to do) and it starts to become a regular thing.
Now that Chloe has become a better person and knows how to appropriately show affection, she's still Adrien's first friend and shows it, but she is a lot more respectful of him, especially once she starts dating Kagami. Both Adrien and Marinette notice Chloe trying, and seeing this better version, they both start to acknowledge a small crush on her (they both already had one on Kagami, but their love for each other was more).
As they start going on more double dates, and hanging out individually as friends, the two couples get a lot closer, there being times where Marinette and Kagami are mistaken for being a couple. Eventually, on a double date where Marinette is flirting with Chloe and Kagami just as much as with Adrien, and Kagami flirting back, Chloe (still concerned with falling into old habits and trying to not act like she used to around Adrien even though now it would be accepted as flirting, not that she realizes that) says something along the lines of "if you like her so much, why don't you date her?". Marinette then jokingly responds with "Kagami, meet my boyfriend (points to Adrien), Adrien, meet my girlfriend (points to Kagami)" as she goes to make a joke concerning Chloe being her other girlfriend, she realizes she would be ok with that, and both Kagami and Adrien seem ok as well, so instead of making a joke about Chloe being her girlfriend, asks her if she wants to be her girlfriend instead.
Chloe is of course confused, but Marinette explains that poly relationships exist, and that if everyone wants to, they can turn their double dates into just being normal dates. Thus polygamy Chloe x Kagami x Marinette x Adrien forms and everyone is happy and together, and now Chloe and Adrien are both flustered messes because they have the full force of confident Marinette and Kagami flirting with them all the time, and don't know how to deal with all this love from these two strong women in their lives.
I had this idea while reading @galahadwilder Notes to Self. Kagami brought up potential polygamous relationship and I thought my only Kagami pairing I like as much as Marigami and Polygami is reformed Chloegami (though, and the only way to get that is to keep Kagami out of a relationship with Marinette. Then I realized that if Polygami was a potential, and there was a reformed Chloe, whose to say Chloegami can't happen as well as Polygami, since a better Chloe and some time would probably give Marinette a new crush, and Adrien seeing his first friend living up to her potential (and be open to the idea that he can like multiple people at the same time and not just brush anyone else off simply because he likes LB) would probably develop a small crush as well, and the best way to integrate the two into a single amazing relationship with the blondes being flustered by the strong women is a friends to lovers double date
