I feel like this is my biggest hot take and I'm not even sure anyone will understand. But... kateve, evekate, dupliatom, whatever. Like hear me out, I have a vision!!
They're both GDA experiments, both on the same team and were friends, both were betrayed by Rex (he cheated on one, lied to the other about no longer being in a relationship), and both are clinging to the remnants of their family, no matter how bad they are. And Kate envies Eve and tries in every way to be better than her, more popular, "steal" her boyfriend, get a boyfriend who is "better" than Eve's crush, and get married quickly. But why is this strangely connected to Eve? Maybe it's a repressed attraction to Eve? Just think, Kate loses interest in Rex immediately when he stops being Eve's boyfriend and she's referring to Mark and Eve's relationship. Regarding Eve's side of things, unfortunately, I don't have such a strong analysis :( I can only add that Eve still clings to Kate, no matter how bad a friend she is, they had those dinners (in the comics). She's one of the few people who understands her and with whom she shares a lot of past/parallels, and Eve has a hard time making close friends
And their pairing would be quite poetic, a girl who dies all the time and a girl who can't die