The Vice-President may simultaneously hold another non-military office in the executive branch.
Once confirmed in this 2nd position, the Vice-President shall serve until the end of the President’s term and may not be removed from this 2nd office except upon impeachment and conviction. The Vice-President may, however, resign this 2nd position.
Upon the Vice-President’s succession to the Presidency, the 2nd office shall be deemed vacant.
Gives the Vice-President something challenging to do, along with a ton of clout and stature. Gives the President at least one person who can tell him the truth with impunity. Removes the humiliation of being VP as Nixon and Johnson were treated; history might have been different had they not been treated so marginally. And gives the VP a record of his own to run on when his time comes.
Food for thought: Maybe give 2 or 3 other members of the executive branch the same immunity from being fired during the president’s term. This would give the President even more people who can safely tell the President the truth.