I agree Pepsi_junkie that your description of events is most likely IF the Supreme Court even hears the case. I also agree that the state legislators will not have the fortitude to do what is right and determine that the number of illegal votes counted, which were counted despite lack of legislative authority as the legislature did not pass election law to allow for that and will roll-over and send Biden electors. However, I would propose that perhaps they can chicken out in another way. They could just refuse to send Trump or Biden electors stating that their state’s election results were too tainted by illegal voting to endorse either candidate. So say Pennsylvania sends electors for John Smith, Wisconsin sends John Jones, Georgia sends Stacey Abrams, and Michigan sends Jim Harbaugh. Then neither Biden nor Trump get the required 270 majority and the US House then elects the President by one vote for each state delegation according to the constitution and the Senate elects the VP. Now if the Georgia run off goes badly we could end up with Trump President and Biden or Harris VP. Given 2020 I could go along with that as the VP position was most accurately described by John Nance Gardner as “not worth a quart of warm spit!”
Good point regarding the possibility that some states potentilly saying “we can’t decide in time so we’ll send nobody”. I think they would know that their political careers were over if they made that move (after all, no votes in their state would count, legitimate ones or otherwise) but that could happen. Then it comes down to how much you trust the GOP to do the right thing in the house.