Mind that this may be going into a bit of Headcanon, but from what I always understood is that Flowey was the past “Player” of Undertale, with him saying that your Saves overwrite his and that a few certain characters caused a fair amount of retries, in that case Omega Flowey would basically be him getting back his “Control” in a sense and becoming a Player, and like the Player he can only really destroy the world, not remake it, which is what Flowey intended to do with all of the 7 Hearts, in that case I don’t really see a problem with scaling to Chara if they truly are just the stats of the player