Not all the cases are federal.
I assume he will lose the election at this point.
What will he do?
Act very badly.
If it's at all close he will try to use the corrupt election officials he has installed to try to avoid certifying results in swing states.
Conflicts will go the supreme court which is very friendly to him.
So if he loses close, he might still win.
Then he will be dictator over a nation that mostly hates him.
As far as violence / civil war, violent incidents very likely but not civil war.
If it's a Harris landslide, then he'll still claim it was rigged but he won't be able to reverse it.
If going along he concludes it will be a Harris landslide well before the election, then he might flee the country or more likely have real or fake severe health problems and exit from the race as the humiliation of losing so badly will be more than his mentally ill self can take.