She ended the acts with her mask on whilst playing, I'm not sure why but there was a theory before that she cries whilst playing and the mask hides her crying face?
Oda seems to make this important detail, plus I doubt Orochi would want her to play with her mask on as obsessed with he with her beauty and how much he simps for her ofc? It's very odd to me.
This small detail is important imo and given BM has just been defeated and stated to be especially by the narrator, only Kaido and CP0 are left now? So I'm certain Act 3 is due to end because of that too.
There is a really slim possibility of the raid failing still imo but I don't think it's gonna happen anymore now especially. If Onigshima really is Enies Lobby 2.0 then Wano can be like Water 7 2.0 and thus we will have an Onigshima Aftermath/Return To Wano Mainland mini arc, maybe 1 more act to wrap up or something?