Mnuchin had no intentions of releasing the GSEs, in my opinion, because it was known that the TBTFs wanted the GSEs to fail so they could get the books of business. Trump, in his letter to Paul said he wanted them released. He delegates authority.. He expects his wishes executed and moves on to another topic. Mnuchin made it look as if he was doing something, albeit slowly, and, essentially, wasted four years. I think it was a stall tactic to keep the TBTFs' wishes alive. We all know they could have successfully released during that time of Trump's term. If Trump was at fault, it was for not looking back and making sure Mnuchin did what he wanted.
Cark Ichan suggested Mnuchin to Trump. I think he did so to help him (Ichan) get the government's hands off the GSEs so he could make another fortune. He held some $50M in GSEs at the time at enormously suppressed share prices. Mnuchin screwed Icahn over as well.