That's $2.1B (minimum) for Jared's hobby rocket.
That does not include Skyfall, which nobody wanted, has no point, and will eat the Mars Exploration Program.
Isaacman was obsessed with NEP in Project Athena, written before becoming NASA administrator. This is nobody else's project or priority.
politico.com
NASA’s nuclear Mars mission to cost over $2 billion
The price tag doesn't include the cost of the science mission the new spacecraft would ferry to the Red Planet.