I broke from my lifelong Republican ranks and voted for Biden specifically to vote against Trump. It won't be a one time favor from me for the Democrats if Trump or one of his Yes-man followers is the Republican presidential nominee in 2024. I won't hesitate to vote Democratic again. I won't vote for Trump or for one of his followers. As a lifelong Republican, I never thought I'd vote Democratic, but Joe Biden is the first Democrat I've ever voted for in any election since I registered to vote in 1992.
I voted for Obama one of the two times as a "protest vote" against the birther conspiracies, but that was before I had started drifting more toward the Libertarian Party.
I had voted republican prior to that, simply because I'm somewhat pro-gun, and in favor of a more conservative tax plan. But when I saw people at McCain's own rally stand up and say the things they were saying about Obama, and he actually had to correct them (and then got booed for his trouble), I knew at that point the GOP was no longer the party for me.
Particularly this moment
When it was Romney vs. Obama, I didn't see either of them as a real "problem", so I voted for Gary Johnson, and did so again in 2016.
I suppose if another Trump-type ran again, I'd have to consider voting against them, but I don't foresee that happening. Major corporations have already pulled (or have announced that they're going to pull) funding from the elected leaders that supported trying to contest the election results, and without major corporate funding, they're dead in the water.
My prediction is, the next "insanely divisive" candidate will come from the left and not the right. Many in the GOP have already showed that they're trying to get back on "their best behavior" (even Mike Pence and Lindsey Graham have been starting to do damage control).
Meanwhile, many on the left are trying really hard to appease the "woke" crowd at every turn (which is something that most people aren't on-board with, as evidenced by the fact that democrats actually lost house seats in districts that voted for Biden over Trump)
Having a 2024 ticket catered to "what 22 year old gender studies majors think the way things should be" isn't out of the realm of possibility for the Democrats.