If you subscribed to the theory that this series will end similar to the original doujin, Yuki gotta play the role as the final antagonist for Gotou. Yuki is probably the only decent guy left for Agawa to turn to if the situation between Agawa and Gotou goes south next chapter. The combination of that and seeing Agawa together with Yuki should set Gotou down to the road of changing his personality for the better.
The author just need give Yuki significantly more screentime/role like he did with Inukai recently in the upcoming. Once Agawa and Gotou do reconcile later, it would be more impactful since Agawa is cheating on Yuki to have sex with the version of Gotou that she wants to see in him.
I don't know what happened in the original doujin, but this looks like Agawa is going to reject Gotou and that will make a sort of downfall for him because after after all what he wants is her, even if he has become what he wanted to be and has girls whenever he wants.
Is not like he doesn't deserve to have more confidence, but probably this kind of fucker attitude is not what Agawa is looking for in him and maybe she is starting to realize she just wants a normal relationship and this Gotou is not someone who looks like it's going to do that. Whenever it's a monster of her own making and it's a little too late to have regrets about it, she also has the right to not like what Gotou has become.
That's if there are feelings on the table, of course, with this author it could be anything. If not, girl, that's a problem you helped to create yourself.