In my opinion, I think it’s gonna be one if not all of the Archons that took part in Khaenri’ah’s destruction by sacrificing themselves or something similar to atone for what they did. Even if they did it for the greater good, a lot of people still died by their hands so they probably feel guilty.
Or Childe, I mean look at his eyes, the dude’s already dead inside.
I think Zhongli has a death flag. Narratively, he’s got nothing else interesting going on, now he’s retired. It’s a natural plot point to have him go out in a blaze of glory protecting Liyue one last time (and also, as you said, redeeming the archons for what went down in Khaenriah).