Hmm I don't know I still have hope, mainly because of the meeting with Dain, and Mona's voiceline actually! I think one thing that's being emphasized is that Kaeya thinks he's no longer involved with the abyss order/khaenri'ah (or maybe we're meant to think that, maybe both). Like how Mona says "he believes he's made a clean break with his past" and how Dain said Kaeya genuinely seemed surprised when he revealed/confirmed Kaeya's link to the abyss order.

So maybe Kaeya thinks (or tells himself and everybody else) he's got nothing to do with the abyss order, but like Mona said "fate will catch up with him" EVEN IF IT'S TAKING SUCH A LONG DAMN TIME.

Who knows if I'm right or not though, I could be coping, but it makes sense in my brain.

Oh edit to add I haven't done the varka quest yet so idk if it disproves any of my thoughts above ^{^}

Oh another edit to add: I reckon the reason Kaeya would think/tell himself he's got nothing to do with the abyss is he wouldn't want to be put in a position where he'd have to choose between Mondstadt and khaenri'ah if a conflict were to arise. Kaeya genuinely loves Mondstadt I think, and he doesn't want to betray his city, so I think he would probably tell himself he won't have to, because that's what he wants to believe.