I don't have any evidence to back this up this is just my headcanon but since i think it will happen i decided to write it so i can say i told you later on well then let's start:
I'm part of the group that believes the raid on onigashima will fail because of these reasons
1: The alliance is not strong enough to beat 2 Yonko
2: Oda said that the Lurking legend who is connected to Wb will appear who i believe is definitely Xbeck and he's not here yet
3: there are many others that have been foreshadowed or just need to be involved in this war like Moriah and grandfleet and Wevil who have not arrived yet
4: in the third act of Kabuki the heroes will suffer a tragedy and the forth act is when they make a heroic comeback and succed and since the tragedy hasn't happen yet and we are already about to start the battle i think losing the battle is going to be the tragedy
So what will happen after they fail? I believe Luffy will be captured, Xbeck will show up and form the Rox pirates again he will decide to execute the fifth yonko publicly to anounce that he is back to rule the seas again which would make all the allies and friends Luffy has like Hancock, Sabo, Coby, garp, the grandfleet and etc... come to Wano and try to save him ( basicaly he is Ace ) and this is the battle that will make marinford look cute.
P.s
Hopefully Garp dies.
I'm part of the group that believes the raid on onigashima will fail because of these reasons
1: The alliance is not strong enough to beat 2 Yonko
2: Oda said that the Lurking legend who is connected to Wb will appear who i believe is definitely Xbeck and he's not here yet
3: there are many others that have been foreshadowed or just need to be involved in this war like Moriah and grandfleet and Wevil who have not arrived yet
4: in the third act of Kabuki the heroes will suffer a tragedy and the forth act is when they make a heroic comeback and succed and since the tragedy hasn't happen yet and we are already about to start the battle i think losing the battle is going to be the tragedy
So what will happen after they fail? I believe Luffy will be captured, Xbeck will show up and form the Rox pirates again he will decide to execute the fifth yonko publicly to anounce that he is back to rule the seas again which would make all the allies and friends Luffy has like Hancock, Sabo, Coby, garp, the grandfleet and etc... come to Wano and try to save him ( basicaly he is Ace ) and this is the battle that will make marinford look cute.
P.s
Hopefully Garp dies.