How would a civil war actually happen? I know this idea gets thrown around, but, I don't see how this would happen.
Usually, civil wars happen with the support of (at least part of) the military and there are 0 doubts about who the army will side with. Even with the high rate of gun ownership in the US (and even higher among right-wingers), there is no way civilians will actually be able to whitstand a focused, concerted military effort.
The only caveat to that is if someone high up in the US military decides that this is their time to act and will try to use current civil unrest for a coup, but that seems extremely unlikely.
Another scenario to consider is an IRA/ETA style insurrection, which, again seems unlikely, as both IRA and ETA had strong geographical and cultural components to their identity, which is not true of right-wing extremists.
What is more likely to happen is for low-level civil unrest to be around for a while, as long as Trump is still in power, but, as soon as Biden comes into effect, the state will step in and very quickly squish anyone they suspect of right-wing violence. Still, it will probably get worse before it gets better.