I'll explain what I did:
I used the working main file, I copied it in the empty Pokemon Sword folder and I renamed it "backup";
I copied another time the main file;
I restored the folder with Checkpoint, but I can't play.
After this, I opened another time previous backup and main file with PkHex and I've got an error message, since the file is too large.
I've not any poke_trade file