I'm trying to transfer a specific world from the Xbox One version of Minecraft to the Series S version. It does appear in my list on series S but when i try to access it, the game says it Failed to Sync World data. I tried using another xbox one to access it, but it gets the same bug. The xbox one i used to play it on no longer works so I cant check it on that console anymore.  I did find an older version of the map on an older minecraft version (the 360 version) but there are years of work missing. I have also tried using the external xbox one hard drive the game was saved on hoping the maps data could be recovered that way. 

There are 4 smaller maps I could load with no issues at all from where the map im trying to recover is saved if that helps.