@Babiapalah clearly she feels guilty about what she did that's why she manipulated his feelings to make him love her again so that she can keep on manipulating his feelings all over again.
what she did wasn't an act of kindness because she has sympathy she knows the MC is sad but does not sympathize with him cause if she did she will stop manipulating his feelings she did that act so that she can keep on hurting the guy. Cause if she didn't it will no longer be fun for her she helped him for her to have more fun not for him.
you can see this kind of behaviors in abusive relationships 1 partner hurt the other then just say sorry and the other person is dumb enough to forgive them. This is what the MC is experiencing so if you are into emotional manipulative people and abusive relationship yes I guess this is comedy.
she isn't like Nagatoro cause you can see that Nagatoro does the bully cause she's about "Stop drawing and notice me senpai" and when senpai notice her, her bullying would decrease there is more flirting than bully in the recent chapters. This girl is different she's not there to be notice or be loved cause the guy already does she's there to have fun with his feelings even after she almost gave the guy depression she won't slow down one bit it maybe she'll slow down after this but I doubt it tbh.
the only way to disprove she isn't a sociopath if she stop being a dick to the guy cause it will prove she was actually nice to stop cause she knows what she did was bad. If she didn't then yeah a Sociopath.