Cruz himself is certainly not mandatory authority on the subject of NBC.
Whatever part of the generic subject of NBC the government has “settled”, it hasn’t settled every possible contingency. Cruz’s case is unique. That is why we have courts - because no law can cover every possible contingency. The Constitution created federal courts to resolve individual CASES AND CONTROVERSIES regarding federal questions as Cruz’s case certainly is.
Cruz’s NBC eligibility is an individual case and controversy of a federal question that needs resolution in a federal court.
“Cruz’s NBC eligibility is an individual case and controversy of a federal question that needs resolution in a federal court.”
Unfortunately, there is still an open question as to whether or not the Constitution allows the judiciary to overrule the decisions of the Electoral College and Congress with respect to the eligibility of the President-Elect and Vice President-Elect. A Constitutional Amendment could rectify the problem, but the establishment politicians have a chokehold on that process and remedy as well.