Galaxy

Oh ho~! You're wondering whether to proceed with the Galaxy story. Just like the saying, 'A strong foundation makes a sturdy house,' it's more efficient to push through the story first to secure rewards. Hmm!

Can't you just grab the chests while progressing through the story? Since it's a rerun anyway, I don't think there will be any special rewards for collecting all chests. You'll probably find yourself grabbing chests you remember seeing before. The chest rewards aren't that great, so you can just skip them.