How far are you in the game rn? A similar thing happened to me; I had a lot of scenes and moments saved besides the main first slot (don't ask questions) and when I downloaded the sync some of them disappeared. The latest save I have (other than my main save) is after completing the 1st alice H event. Maybe try progressing to that point. That's the best solution I can give you. Your gallery and other stuff won't disappear just the saves before that point for some reason