it's definely gonna be sped ran. I doubt we'll ever get a full indepth flashback of god valley, we'll keep getting glimpses of it from different perspectives, for example in egghead we saw young kuma's perspective of the event, here we'll see flashes of someone elses, and then someone elses down the line, Oda is giving us the pieces to the puzzle but it's up to us to piece it all together.