Trump can actually get exactly 270 electors just by holding serve where he's supposed to and sweeping Pennsylvania, North Carolina, and Georgia. There is a very plausible scenario in which Trump hits 270 and gets the race called for him while all the other swing states are undeclared. Then all of them flipping blue under mysterious circumstances and bringing the total to 270-268 creates a scenario where just one faithless elector could cost Trump the presidency, assuming the Deep State cooks up some Russian interference bullshit as a fig leaf to get one guy to flip. If you're looking for a shitshow scenario to kickstart a civil war, something like that could well be it.
The election everyone votes in determines whose electors get to decide the President. There are so many electors for both the GOP and Dem side for each state. So if one of the members of the GOP slate who gets appointed flips, that vote would go to Kamala.