So, by law, those hundreds of thousands of late votes should be invalid?
Late delivered ballots are invalid, if thats what the state law says. Executive orders, like declared delivery extensions, cannot preempt law. Keyword is delivered, which is the time the ballots arrive at the place(s)where they are to be counted.
Bush v. Gore turned on compliance with state election law. IMO, it would be malpractice if the Attorneys are not briefing and filing Requests for Injunctive Relief right now