With that said, it is highly likely that Monika's powers become completely nullified if she was somehow able to leave the game (which she actually tries), whereas Goku's powers stay the same in any reality or universe, so this is highly dependent on context.

I still doubt Monika would win against Goku since he has no character file to manipulate and he is not in the DDLC universe, essentially turning the fight into planet buster VS regular highschool girl.