I don't think changing stat cap would change the balance of the game that drastically, to be honest. Because it's more about changing the end game than beginning and mid game. To give players something to work on. With a much higher factor ceiling would make having a full team of all 'perfect' characters unviable as it would take too long or get too tedious, which would encourage players to focus on a few characters they love (aka their favorite waifu/husbando) to make them feel more unique... while also make the characters they don't invest more unique as well as they would be differentiated based on their initial stats.
As for the balance of late game... you honestly don't even have to design encounters with broken characters in mind. Just go with what you already planned for the end game. Having brokenly OP character for end game doesn't have to be a bad thing, it can be a reward for players who breeze through any encounters with their favorite waifu/husbando.
But yeah. That's my two cents at least. My opinion is this game right now need more content both for story campaign, and for free play element as well. It doesn't need more quote unquote, 'balancing'. As all it does is gatekeep the content of this game and make everything more tedious and unfun to play.