A Motion to Dismiss should follow upon arraignment.
Based on the fact that the investigation was initiated when the Archive requested it. But the Archive has no statutory authority to seek DoJ involvement when a former President is involved. The statute authorizing the Archive involves agencies only. See:
44 U.S. Code § 2905.
That should suffice for dismissal.
I further note that Jack Smith never references the sole statutory construct (PRA) that applies to a former President and his dealing with the Archive. No wonder!
Nothing in the PRA authorizes DoJ intervention, it is solely a civil issue between a former President and the Archive.