I think it is psychologically impossible for Trump NOT to get PERSONALLY involved. If he does go down, it will be because he cannot restrain himself and because he believes he is invulnerable and does not need to protect himself.
Barr's job as AG is to make sure the DoJ is functioning properly, which is has not been for some time now. His job is to fix that through institutional change, not personally prosecute cases. He has to put the right people in charge of such things and call out when his subordinates are not following the policies as established by the chief executive.
Part of that institutional change has to be making sure that law is applied equally to all. Coup plotters must be rooted out for this to occur.