The Chinese regime is responsible for the spread of the COVID-19 virus. Only the extent of the regime's culpability is in question. That should be resolved legally if possible, not only on behalf of the United States, but all nations affected by the outbreak, with appropriate financial restitution and security safeguards as compensation.
The U.S. government itself can seek legal recourse against China in the International Court of Justice, or through the establishment of an ad hoc international tribunal. Since America is hardly the only country that might benefit through such action, garnering international support should be doable, despite China's clout. China would have to agree to subject itself to such a proceeding. But a rejection would be tantamount to an admission of guilt, and then help underpin any other unilateral actions the U.S. might take. International courts and tribunals historically are not much to America's liking, but occasionally -- as at Nuremberg -- can serve important purposes. This is one.