I think it's worth pointing out that when it comes disciplines like dancing, they are not really being studied extensively by the leading aethorologists of the world. Dancers just say they are manipulating aether through thier dance because that is what they understand "energy" to be. It might be aether, it might be dynamis. I don't think enougn in-universe research has been done on Dark Knights or Dancers to know.

Though I like to imagine some Hannish alchemist writing a paper theorizing that Dancers are using akasa, and it failing peer review because they had no way of proving it at the time.