So what exactly is this asshole doing when not making King Drasil and the royal choirboys seethe?

So question. I plan to play NG+ and am interested in mega difficulty but I have to ask. I Ideally want to take my team and reset them all back down to rookie stage and play through naturally. I found hard mode a fucking joke, but is mega mode going to be too hard for this sort of approach? A google search told me all Digimon on mega mode have 9999 in every fucking stat. Does it expect you to play through it with megas the whole way?