Something I read that was in response to my saying that President Biden should pardon any/all he wants to, whether accused or convicted of any federal crimes: can’t use a pardon on anyone unconvicted of a federal crime. There is no prophylactic pardon.

NOT TRUE. Ask President Nixon. He was never indicted. He never went to trial for any crimes. He was never convicted of any crimes. President Ford gave Nixon a pardon for crimes he may have committed.