Which 538 impeachment scenario is most likely?

[Absentee Voting Ghost of Ruin]

All of these are way off. Donald Trump is by turns increasingly incoherent and dictatorial as impeachment and related subjects put more cracks in the Republicans of Gilead's demented fantasyland.  Something is going to break in the next year. Whether it will be Donald Trump, the Republican party, the Democratic party, or our nation, I really don't know, although I lean towards some sort of catastrophic meltdown by Donald. At the same time, I find it horrifyingly plausible that the current GOP (both politicians and ranks and file) will support a raving mental incompetent come hell or high water. If he does fall, I'm also not sold on Donald's departure automatically leading to nominee Pence, especially if it comes sooner rather than later.

Key questions to any outcome:

How long can his family, his staff, and the media keep Donald's insanity smoothed over? Although the specifics aren't clear,  he's not mentally competent and is nastily insane. At some point he won't even  be able to rant at his redhat Nuremberg rallies. Will that be soon enough to deny him the nomination? Will something leak and subject his mental health to the sort of inquiry his criminal Ukrainian conspiracy has?

How far down the path of tyranny are Republican office-holders willing to go? The GOP is far down this rabbit hole already. My personal opinion is that they'd be perfectly happy with a one-party white nationalist dictatorship, as long as they could pretend it was a democracy. Hopefully I'm wrong.

Is there any point at which Republican voters will, like schooling fish, all turn in a different direction? My personal opinion is that Republicans have gone full Jonestown, and will murder their neighbors, their children, and themselves rather than give up on "owning the libs" but hopefully I'm wrong on this, too.

Will the Democratic nominee be able to rally young and anti-Trump voters?
A significant increase in turnout among demographics that do not support Republicans or Donald Trump will lead to a GOP worst-case scenario. (If we actually have a free and fair election.)

Do any major crises that impact the general American public happen in the next year?
Probably not going to change  a lot of minds, but could lead to a small if significant shift in support, and/or expose Donald's incompetence.