Right now there’s a massive glitch where if you shut off your switch or your internet functionality at any moment leading up or during the fight with the final boss, it will wipe that data completely and make you do it again. The game just came out, so right now there is no patch to this glitch, and it essentially forces you to play through another 1-2 hours of the story AGAIN. I say this because this just happened to me, and apparently it’s happened to many other players. For now it’s best to just avoid the final boss altogether, because who knows if it’ll actually be worthwhile or not if/when the devs patch this out.