Worlds disappearing/others setting to prior phase one aquatic

I had been creating a new world on a bedrock edition since the first wave of the Aquatic update released.I also updated a 360 maps I have been working on since the first month creative mode released.On July 6th my Xbox One x stopped working.I filed the report to send it into  Microsoft .So I installed Minecraft bedrock edition on my other Xbox one.It said my saves were  corrupt  For both of them.Says to try playing on the original console.But a older save of the bedrock survival was fine.It was about a month before.I just got my Xbox one x back.The survival save that wouldn’t load can’t be found,only the earlyer save.The creative mode 360 save was on the synce list.But when it does upload it,it is missing about 85mb.It reset prior phase one aquatic update.It is still on the synce old world list,showing the larger file.But loads to a much older version.Could you please give me insight on why they lost about 3-4 weeks of saves? Thank