maybe in the end .. u become the bad guy and the fatui was just trying to protect teyvat all along . you see all the archon all like dead beat dad to their people with personnel issue...
Protect Tevyat also cannot whitewash plotting events/wars will that will kill many people.
I will pick some lines from wiki
https://genshin-impact.fandom.com/wiki/Fatui#In_Mondstadt
Mondstadt
During Eula's Story Quest, it is revealed that some members were colluding with Schubert Lawrence to invade Mondstadt, promising to help him establish the Lawrence Clan as the rulers of the city once again, though this plot was quickly foiled by the Knights of Favonius.
Liyue
Fatui soldiers assisted Childe after he summoned the Overlord of the Vortex in order to draw out Rex Lapis, fighting against the Traveler, Keqing, and the Millelith on the Jade Chamber. Since this was effectively abetting a plot to destroy Liyue Harbor.
While relations have soured since Childe's actions, the Fatui still has a delegation in Liyue and is still interested in the nation's politics — upon learning that Uncle Tian had wanted to step down from the Liyue Qixing, they colluded with one of his disciples, Zhiyi, to assassinate and replace him so they could have influence over the Liyue Qixing. Fortunately, this plot was foiled by Yelan
Inazuma
The Fatui were the masterminds behind the Vision Hunt Decree in Inazuma, and fanned the flames of conflict on both sides of the Inazuman civil war. They colluded with the Tenryou and Kanjou Commissions to feed the Raiden Shogun false information[25] and gather materials for their Delusion Factory respectively, secretly distributed Delusions among the Watatsumi resistance forces, and planted spies throughout the country in various efforts to destabilize both Watatsumi and the Shogunate and render them vulnerable to Fatui influence.
Sumeru
Fatui involvement in Sumeru has largely been from the Harbinger Il Dottore's projects. They collaborated with the sages of Sumeru Akademiya to replace Lesser Lord Kusanali with a new god of wisdom.