I honestly believe Big Mom is going down here, one way or the other. I don't see Oda bringing her as an antagonist for another arc as well, especially considering all the screen time she has already had and how long ago her conflict with the straw hats started without still being resolved. Her name has been tied to that of Kaido since forever, since Thriller Bark. I see them falling together as well.
I don't think that he would have brought her to Wano and make her stay the entire arc if he was planning for her to be defeated somewhere else.
And Oda has still to focus on the two most relevant emperors as well, Shanks and Blacobeard.
I don't see her beIng defeated by force here, nor that her story will be over in Wano.
As I have mentionned before the great majority of her children and crewmates such as Katakuri, Cracker, Brûlée, Pudding, Snack, Oven, Streusen and Tamago are absent from this arc and only Perospero has joined her in Onigashima.
And I don't think that we were told about her history with Elbaf and the giants if we're not going to see interact with giants in the present story, especially as two members of the Grand Fleet have personnal history with her, especially Gerd, and that Lola has come back (in a particulary bad way) in the New World.