There is generally no legal penalty for the US government, or individual government officials as a matter of policy rather than subordinate individuals going rogue, breaking the law; the remedy is generally just being ordered to stop breaking the law. There may occasionally be compensation to those injured, but even when that occurs it is distinct from a penalty.
Penalties for illegal policy, if they exist, are generally political and dependent on the electorate (or, in principle, Congress.)
SCOTUS believe it's up to congress to try and convict him, and Republicans in Congress believe it's up to the courts to try and convict him. Neither will lift a finger to save you or the republic.
The legislature can at any point in time choose to convene a kangaroo court to punish him, but the Republican party has actively and deliberately emasculated itself when it comes to holding their Don accountable - for anything.
My personal take is that the courts are generally accepted as not impartial, so punishment is also accepted as optional since both sides know it's theater. If you disagree, my question is why did it take 6 months for the decision if it's not theater?
Essentially sovereign immunity exists, because there is a collective entity problem and circular liability argument that applies to penalties for the government.
Since we fund and elect the government, we are essentially all collectively responsible for the government, and with our tax dollars we are all collectively liable for the government debts.
In many cases, it doesn’t make sense to penalize ourselves and thus the government often has sovereign immunity in many cases.
The enforcement penalty of the constitution is the state's ability to rescind delegated powers from the federal government. No one seems to think it's bad enough to be worth having a real conversation about that.