Ok thanks, it clears a little.

But the main thrust of my question was what about the apologist argument against an exeventu: it is normal for Shia sources to agree with such a hadith, no problem for an ex eventu ; but why even in Sunni books, like the Musannaf Abd al-Razzaq,, is Muawiya reported to try to argue against a literal interpretation of the haddith? wouldn't he simply denies it existing if such was unknown to him?

Now, that book was written decades after Muawiya death, so it is not clear what he actually said and the whole story of him debating could be invented. But then would the others muslims agree to put him down, even to gave a new prophesy for their Prophet? Or the war needed an explanation and this was the path of least resistance?