It should be a bit easier since you take less damage and you do more attack, did you read all the text for 21-2 and on?
It’ll hurt sure, but it won’t kill you. It’ll do about 6-8k dmg to each of your characters. Not completely terrible, but not something to overlook either. So just make sure your Mash gets her defense buff up for everyone and it shouldn’t even be that bad.
Edit: Oh and by the way, I totally half-assed a fight against Georgios in CCC. I only borrowed gramps but i managed to deplete both of his Break Bars, first with 330k, and last with 220k or something like that… lol. Only my Jeanne and Nero were alive at the end.