Most likely 5 as the japanese plays. Anyway, now that I think about it, this means we are not even close to the half aka act 2 will most likely conclude with the onigashima raid, probably the start, not the end, they will maybe show also the reactions ofbthe world to the Kaido BM allaiance and show a lot of people coming to Wano (we will probably finally see green bull at least) act 3 has to close with the end of the raid and the start of the real war with the landing of the big shots on Wano which will wage for the last 1-2 acts.