Game crashes when trying to convert old world

When I try to convert my old worlds from Minecraft xboxone edition the the conversion process starts fine but then once it reaches 40% the game crashes and return me to the xboxone dashboard. I’ve tried at least 30 times one different versions of the game hoping it will some day work but I’ve had no luck. I read online people talking about opening the map in xboxone edition and resetting the nether then export the world again to fix the issue but I can’t do that as you can no longer play xboxone edition even though I own  a physical copy of the game. I hope there’s something to you can do to fix it because I’ve spent years playing on that map thanks.