I don't think they are losing really. Like I 100% expect the raid to be successful down below.
What I dont expect is the fight to be capped off on the roof. Too many characters still MIA on mainland Wano and now a plotline seemingly being relegated back to Wano and not Onigashima.
People really shouldn't be discounting the idea that the fight could be temporarily lost on the roof and then resumed later. Oda has done this with Luffy multiple times in different ways. Its not actually a new thing.
I'll im saying is to wait the next 3-5 chapters and see what actually changes on the roof. If its meant to be the location of the final battle, so be it. But if its not, it was already called for