Theory on the Female Titan
The reason the Female Titan’s power is both mimicry and femininity isn’t because it’s either or strictly or because one is of the other, it’s because the Female Titan is meant to be an abstract representation of the Progenitor Titan, Ymir’s original Titan that had the power of all Nine. Hence why it has a female body as Ymir’s Titan did aswell, and why it can mimic other Titans, it’s mimicry is like a much lower level version of Ymir’s wielding of all Nine Titans.