Relevant: acceptance of a pardon is acknowledgement of guilt. This was adjudicated in Burdick v. United States in 1915.

Another fun thing is if you are pardoned for a crime, the 5th amendment no longer applies as your testimony is no longer incriminating; lying is still perjury.

Putting Fauci on the stand and forcing him to admit to his crimes would still be effective. And the pardon isn't for any of his staff, who are probably themselves guilty of various offenses too.