For me it is Chloe from Detroit Become Human. I like her because she is beautiful, expressive, she breaks the fourth wall and evolve alongside with me the player. It is like she is being affected by my choices in the game.
(...) or simply annoying the player and keeping them from engaging in chaotic behaviour.
From my experience having watched dozens of people play DE at this point this part is only half true. A vast majority of players inadvertently hamper their experience by missing out on massive amounts of content out of fear of "disappointing Kim". I couldn't even tell you how many people I've seen never learn about the Pale because they were afraid of telling Lena they don't remember reality in front of Kim. Though in part of course this is people being trained by all other RPGs that "wacky" dialogue options punish you - which is something Disco doesn't do.
Apart from that I completely agree with you and think overall Kim is probably the best written character in gaming and a tour de force of subtlety and nuance.