https://en.wikipedia.org/wiki/Royal_prerogative_of_mercy
here is some history on pardons.
One of most controversial was Pilates pardon of Barabbas. It had some interesting effects.
You are really reaching here, unless you are saying that the people will break the law because Biden pardoned his son.
I do not see that happening. At best is to bring charges against Hunter, if we can get Trump elected, in Trump's triumphant return. I won't state how that might be accomplished right now. Because sometimes it is not wise to talk about certain things until the time is right to do so.