Hand your backup from the phone to this computer. No account, no file to move.
Counted shows this on your phone under Settings → Send to this computer.
Send to this computer.Your phone encrypts the backup before it uploads anything. The code is two halves: the first six characters are a locker number, and the last sixteen are the key. Only the locker number is ever sent to the server.
The key half stays in this tab. The server holds bytes it cannot read, throws them away after 24 hours, and this page deletes them the moment the transfer lands.
Your backup is then kept in this browser on this computer so the dashboard opens straight into it. There is a Forget this file button there whenever you want it gone.