It's not related to the existence of a poke_trade file.
I loaded your main (and a copy of the main renamed as backup), with a poke_trade and it works fine.
Look, my previous post has a screenshot that has your trainer card.
Make sure you have the latest Checkpoint, make sure both main and backup aren't corrupted, then try again to restore.
If it continues to not work, go into settings for your Switch, delete the save file, play Sword again and save as early as you can, then try to restore the save after that.