Personally, I don't find Evangelical support of Trump all that surprising.
When you get down to brass tacks, this is an election between two candidates. Almost no one is going to look at those two candidates and find a perfect fit. It's quite possible that people won't even find a good fit. But, they have three choices, either one of the candidates or not voting at all. The latter of those choices is pointless, if one has policy preferences that they want to achieve. That only leaves picking the closest fit among the two candidates.

In may corners of Lemmy, and in this community specifically, there has been a very strong push towards the sort of "vote Blue, no matter who" message, which has been around for several cycles. And this message is not wrong. Harris's position on the war in Gaza has a lot of detractors. But, the choice is not between Harris and someone with a better position. The race is between Harris and Trump, whose position on Gaza is likely worse for those detractors. If those detractors don't want things to get worse, they pretty much have to accept the situation as is, vote Harris and push for changes. And I suspect a lot of folks will support Harris, some enthusiastically, in spite of that policy difference. Because they will find other policy positions that they strongly support are also supported or championed by Harris. Better a flawed candidate that one which is diametrically opposed to the policy positions which one holds most dear.

The thing which seems to be forgotten by folks who wonder "how can Evangelicals support Trump?", is that this same problem cuts both ways. The people who hold GOP aligned policy preferences hold those beliefs just as strongly as Liberal/Progressive folks hold their own. That they would fall into a "vote Red, no matter who" mindset should not be surprising at all. And for Evangelicals, I'd argue that this mindset may be even stronger. These are folks who believe that, not only does this life hinge on their actions, they also truly believe that the here-after does as well. As much fun as we might make of people for believing in an invisible sky-wizard, they really, really believe all that stuff. And their entire self-identity will be built on the version of that belief system. And let me stress that it's specifically "their version of that belief system". The various versions of the Christian Bible have a lot of ambiguous and contradictory stuff in them. It's easy enough to dig out justifications for nearly any positions one wants to take. And Trump's messaging has been pretty well aligned with the mainstream Evangelical version of policy positions on all the major topics. Harris's positions, on the other hand, are in direct oppositions to those positions.

Why does that matter so much? One of the deeply important policy positions to Evangelicals, for several decades now, has been overturning Roe v. Wade. And for all the shit one might say about Trump, he actually got that done. Nixon, Regan, Bush, and Bush all failed in that one, paramount goal. Trump, did it. Stop and imagine for a moment, a politician whose personal life you find distasteful, yet they managed to accomplish the one single policy goal you hold above all others, would you go vote against them? Especially when their opposition is loudly campaigning to undo that major policy win for you? Oh, and that opposition is also campaigning against just about every other social policy position you hold. Anyone saying "yes" to that question is bullshitting themselves.

Now, is Trump going to get anything else done for the Evangelicals? Who knows. But, Harris certainly isn't and she's actively hostile to their worldview. And Trump already got "goal number one" done. It seems like a reasonable bet that someone who already won the top line fight might win a few of the other ones as well. And all that "fascism, threat to democracy stuff"? Ya, that's just liberals whining because they are losing. It's Godwin's Law in action. The lawsuits and criminal convictions, that's just liberals weaponizing the DoJ to stop Trump, since they can't stop him legitimately. And Trump's past as a horrible person? A personal turnaround story of a "lost soul coming to Jesus" is damned near a foundational myth of Evangelicalism.

No, Evangelicals supporting Trump is neither surprising, nor unexpected. And you can bet they will latch right onto the next GOP candidate to come along. And it's not all that hard to understand. If you have ever bought into any version of "vote Blue, no matter who", then you are intimately familiar with the same logic. From their perspective, the US is in the grips of an existential crisis which is being perpetrated by Democrats. The very foundations of their self are "under attack" as society moves further and further away from their central truths. And, from my own perspective, I don't see that there is really any way to convince those folks otherwise. Trump isn't the Devil in the desert tempting Jesus. To them, he's the flawed man who is going to save their version of the US the only way he can. He's a vigilante, bending or breaking the rules, because the rules are stacked against "the righteous". That's the mindset you are up against.