I know this could have gotten confusing so here is a plot summary/ what I was thinking of while writing this.

In the future, Gabriel had 'given up' being Hawkmoth and started dating Nathalie though they were never public and they both kept their respective miraculous. Gabriel, still obsessed with Emilie, tells Nathalie he is going to akumatize someone, Nathalie gets upset because she doesn't understand why she isn't good enough. Nathalie transforms and runs off as Mayura but Adrien sees her transforms and so he follows her as Chat Noir. He tries to comfort her and Mayura ends up telling Chat that she is upset because of Hawkmoth. While Chat still doesn't know who Hawkmoth is, he doesn't like seeing Nathalie sad. This leads to the both of them to be akumatized, which, similarly to the episode Chat Blanc, ends up destroying Paris. Bunnyx takes Ladybug and Hawkmoth to the future to save their partners. Since Mayura had been upset at Hawkmoth, her believing that he might have had good intentions and still loves her is enough for her to fight the akuma (even if, at this time, Hawkmoth is lying to her). Since seeing Mayura upset had ultimately been why Chat Noir got akumatized, knowing that she had forgiven Hawkmoth became enough for him to fight the akuma as well (though this was also my laziness of not knowing what I could have done as a shared akumatized object). Hawkmoth does, however, not like seeing Mayura injured and realizes that she might be more than he originally thought.

In ending one, his recent events make him realize how important Nathalie is to him. To prevent what he saw he is relying on himself to put Nathalie ahead of everything else.

In ending two, he thinks it's safer to not even start a relationship with Nathalie. To keep his distance from her, he becomes more cold and cruel but only towards her. This results in Nathalie leaving, and while it hurts the both of them, Gabe thinks he is doing the best thing to protect her.