If 46 states followed the rules but four states didn't which greatly altered the election outcome then the other states had their votes invalidated. Thus the harmed States have a right to go to the Supreme Court for relief. Doesn't mean the Supreme Court chooses the next president. If the SCOTUS rules in favor of the suing States anything done by the four States that was unconstitutional must be undone, as in not counting ballots that came in past the deadline. If the state legislature says ballots must be in by 8 p.m. election night then under the Constitution that is what must be because under the Constitution only the state legislature can make that call. If however a judge or election official allows ballots to continue to come in, or any other number of things that the state legislature didn't decide on, then that's unconstitutional. They don't have that authority when it comes to elections, only the state legislature does. You may very well get electors chosen by the legislature who still vote for Biden. We'll have to wait and see.