What is a more compelling message than "All your problems are the other side's fault and I will fix them instantly and without pain to you while making sure those you hate and fear suffer?"
If you have the moral apathy to craft such a message just to win, that cannot be combatted until the 1) consequences of electing such a person are made clear to those who supported him, and they stop supporting him or 2) you are willing to get down in dirt and craft exactly the same message, which those with moral decency won't do.
Herein lies the problem and why Democrats are in complete despair -- because number 1 happened in 2020, and after defecating on election integrity without evidence, THEN Trump attempted to foment a coup.
So one would think that such actions after already rejecting him democratically would translate into a "never again" approach by the voting populace. Isn't that logical?
But it didn't.
In fact an even larger group bought the same line all over again, even after his post-electoral actions proved him unwilling to step down peaceably until his options were exhausted.
Now I am already on record saying Biden should have announced he was a one-term President after he won or, at the latest, after the mid-terms. And I said so then, so this isn't hindsight, and maybe that's the, or a, problem.
But it has nothing to do with "introspection". When the other side is willing to do and say whatever it can to win, regardless of consequences, you must of needs rely on the populace to see that as a leadership failing. And not enough of the populace could. And in fact, many embraced this approach.
How can you not denigrate (some of) them?
I took time with this post because it's impossible to critique.
All things are solvable in the land of lies, but as you pointed out it's more than that, to go back for second helpings after all the shit Trump pulled off the first time, to ignore his appalling behaviour these last four years, and all those skeletons tumbling out of closets that expose Trump for what he really is, it's almost incomprehensible that such a man could be elected again.
But in order for all this shit to matter, it would require Trump supporters to care, and they clearly don't.
Why?
For his transgressions to matter they'd have to happen in their world, but they didn't happen there, they happened in your world, a mishmash of Rich Men North of Richmond, Rachel Maddow, Hollywood woke world, a world that exists in the same time and space as theirs, but one where you have all the power and they have none, all that shit he pulled off? It's a pity he didn't do more, for them electing Trump is giving your world a big fat finger fuck off.
But more than having all the power, the thing that hurts the most for Trump supporters is your world's perceived indifference, it isn't even contempt, it's your indifference (when I say you I don't mean you personally) well you're not indifferent now are you!
How do you combat that? As you say you can't lie with ease like Trump, wiping problems away with a wave of the hand, or in Trump's case a pen.
Well the Democrats have to ditch identity politics for starters, or at least some of it, and get real about the structural inequalities baked in by America's brutal red in tooth and claw capitalism. Get yourself a universal healthcare system and build a lot of houses, tell the people you're going to do it and if you get in do it.
Will the Democrats do that?
My guess is no.