I get the same problem. I have tried downloading my world on Windows 10, Switch, Xbox, IOS and Android and all fail at the level import part. My world is ~380mb and when I try to download it it downloads ~519mb and gets to 100%. This started happening after I applyed the vanillabdcraft texture pack. I feel like it is trying to download the texture pack along with the world but I have tried downloading the backup before the texture pack and after at multiple time instances. I have also tried restoring the world before and after I applied the texture pack at multiple time instances and then downloading the world but still get the level import failed error. So in summary I have tried on basically all editions and all possibilities of downloading my world. I also made sure I reinstalled minecraft for a fresh new version before trying. This is why i feel like it is the texture pack causing the problem.
I get the same problem. I have tried downloading my world on Windows 10, Switch, Xbox, IOS and Android and all fail at the level import part. My world is ~380mb and when I try to download it it downloads ~519mb and gets to 100%. This started happening after I applyed the vanillabdcraft texture pack. I feel like it is trying to download the texture pack along with the world but I have tried downloading the backup before the texture pack and after at multiple time instances. I have also tried restoring the world before and after I applied the texture pack at multiple time instances and then downloading the world but still get the level import failed error. So in summary I have tried on basically all editions and all possibilities of downloading my world. I also made sure I reinstalled minecraft for a fresh new version before trying. This is why i feel like it is the texture pack causing the problem.
I finally found a way to unlock the acheivment on Xbox one. You have to be in a local world with mutlitplayer turned off.