>Her games don't interest me
She's one of the few that actually plays games, though. 99% of the other girls just play autism simulators and shitty FPSs.
>Also she seems oddly passive aggressive against Pekora for some reason
She did the same thing with Aqua. She just doesn't know how to talk to people so she takes the "bully" approach to breaking the ice. She doesn't do well as the subject of bullying because she laughs at everything and she has trouble keeping a straight face when putting on a super sweet, polite persona. So, unless you're someone like Fubuki, Miko or Okayu, who are really good ice breakers, she'll have trouble getting close to you.
If you noticed, in both her Pekora and Risu collabs, she talked to chat a lot, saying things like, "Isn't she mean/cute, guys?" Because she's close to chat, she can't stray far from those she's close to. And in the train game with Aqua, she couldn't talk to her at all, which was the big joke of the collab. Whenever they were alone, they just stuttered and stumbled over their words.
It's not her being mean, she's just shy. Aqua and Pekora are the same, but they handle it differently. Aqua handles it by shutting up and doing whatever she's told; Pekora handles it by setting herself up to get bullied, because her whiny reactions are funny and help break the ice (see her with Miko or Okayu). Okayu was actually more popular than Korone at first because Korone was so reserved, but Okayu helped her out of her shell, just like Miko helped Pekora.