I think there's a lot to talk about here, but I also don't want to direct any of it toward other players. I won't begrudge anyone their readings and I definitely don't presume to speak for others on the subject.

That said, I do agree that the morality in the game is fraught. My personal hope is that the Tsaritsa (and the Harbingers alongside her) will enjoy the nuance the narrative has thus far teased. Despite what we hear of the Fatui, Childe calls the Tsaritsa a gentle soul who has had to harden herself, and who declared war against the world because she dreams of peace. This makes her an incredibly compelling Archon to me. For all that the traveler seems to be friendly with the Archons we've met so far, we've also seen the Archons do troubling things. ("Caribert" shows just how horrific their power can be). The six sins of the Akademiya (which we learn through Cyno's character story) speak to the fact that the those in power seem to want to hide some knowledge from scholars who threaten to come close to figuring out the truth of the world. The Harbingers seem to share an "ends justify the means" mentality, but the ends themselves don't always seem downright evil. Dottore's research into Eleazar lacked ethics approval, but he did ultimately manage to cure it before his experiment was shut down (this isn't intended to excuse his process, but rather to say that, for all that tampering with life and death is a "sin," the practice of medicine isn't inherently evil).

Ultimately, I hope we'll find a reason why our sibling is doing what they're doing and a reason why we have to go on this adventure to figure it out ourselves (beyond just "it's a game mechanic"). My hope is that we continue to uncover nuance as we progress through the story.

Also, we go around killing hilichurls, so our hands aren't exactly clean in any of this.