Just picked up Divinity Original Sin 2, and it looks like exactly the kind of game I've been searching for, excited to play. Just two questions before I dive into it;

If I pick a hero with an origin story, is it better that I not edit their starting class/skills/etc, and leave everyone in the class they were given, or should I change things around? I'm under the impression it doesn't change the story, but wondering if it's just a bad idea.

Also, is this a game that rewards you messing around with builds, or are just looking up builds a much better idea? I'm fine with messing up, but if this is the kind of game that becomes unplayably difficult if you're not close enough to optimized, I wanna be ready for that.