You have to prove it well enough for the SCOTUS to order the state legislatures to do their jobs. SCOTUS is an appellate court. The state legislatures will most likely only act if they are ordered to do so or if certification is bogged down in the courts and the safe harbor date is approaching, much like 2000. Even then it isn’t certain that they send a slate of Trump electors. Continual shows of support for Trump might motivate them, or absolutely convincing evidence of fraud.
Didn’t President Trump get a recent case expedited to the supreme court?
Isn’t there some emergency process for doing so?