You're assuming there actually is an Individual X. It is possible he was fabricated in order to hide that the Feds indeed did gain the password for the wallet.
"On November 3, 2020, Individual X signed a Consent and Agreement to Forfeiture with the U.S. Attorney’s Office, Northern District of California. In that agreement, Individual X, consented to the forfeiture of the Defendant Property to the United States government."