More than being jealous I think that he hate Naoya.
They are two people sharing the same body, but Naoya decided to stop replying on Yuuya even if this means that he will get hurt, and he also decided to not switch with Yuuya anymore. For Yuuya, Naoya tried to get rid of him, so he is trying to do the same. Moreover, when Naoya got rejected, he tried to kill himself which would have result in Yuuya death, but Yuuya want ed to live....
It is so damn psychological
I doubt if he really hates Naoya. For me, he actually wants to be Naoya's friend and he really wants to help but now he's pissed because Naoya doesn't want him to reappear. In short, what he's doing right now is like a child seeking attention from the adults
The way he manifests that he is pissed is childish, but bring upset against Naoya is legit for him.
I mean, Naoya tried to kill himself and Yuuya only because he got rejected by someone.
I think Yuuya is just being jealous of Naoya and he just want to be in a spotlight that's why he act this way. I guess in the end, Yuuya may disappear (integrate with Naoya)