Jack Smith is legally not the top prosecutor in the case as I understand things.
He is there for the purpose of assisting DoJ staffers.
Who is then?
Fruit of the poisonous tree. Smith has been the face of it, complete with press conferences explaining his reasons for bringing charges.
I’m no legal strategist, so I don’t know, ... perhaps Smith is the fall guy and the DOJ will sacrifice his reputation, law license and career to protect those DOJ insiders and allow them to continue their efforts to destroy Trump in the background.