if you were the president and feeling completely unrestrained: "Yes, you US Marshals who answer to me, the President: I am directing you not to serve any writs that come from that Court."
and then so much for civil remedies
If that's the scenario, criminal liability - particularly given that the President can pardon criminal (but not civil) contempt and was already immune from prosecution while in office - was never going to be a restriant.
Law is the process we've all agreed to follow before somebody with a gun takes you or your stuff. If the people with guns stop answering to it, it stops having force of law.