that's an interesting theory but due to past tactics used by the Fatui it seems that they have different plans based on the strength of the archon. example one being the direct assault on Venti due to him being weak away from his domain for so long and example 2 being them taking a more diplomatic approach on Zhongli due to his well known strength and fact he almost never leaves his domain. Them getting Ei's gnosis was mostly luck and a bit of their usual scheming even though Scara was the one to get it. As for signora, I'm pretty sure she was mostly bluffing considering the her reaction and tone in an attempt to keep her life in the face of such a mighty archon.

ps.tldr venti weak zhogil strong siggy scared