I think she is/was the saintess.
But then her daughter became the new saintess.
The priests were already loyal to the Öls saintess.
And as the new priest came, the daughter was already the new saintess, or at the stage in becoming one?
And that's the reason, she isn't loyal to the old one.
At least, that's what I think.
According to spoilers, a few of the Saintess' Wings are real, but half are fake (they have powers like real Wings but their source/god is evil).
So Noelle's boyfriend is a real Wing, but his loyalty hasn't transferred over yet (since the FL is only NOW awakening to her powers).
And yes, the Saintess was only supposed to be a temporary Saintess (which she knew upfront before accepting those powers), but she got corrupted before the power transferred over to her daughter...somehow. (I didn't get that far in the novel.)
I think the brown hair girl is probably the only real reincarnation of the original Saint’s wings the others don’t really seem genuine but the white haired on is probably just bewitched by the bitches devilish magic or something