Agree with much of that, though, I would say that Reagan’s “shining city on a hill” was predicated upon the existence of a possible dark, almost apocalyptic alternate America, which he alluded to quite regularly, both on the campaign trail and in office. He used stark contrasts and charged (racist) rhetoric to make a case for America needing to be “saved” from the barbarians at the gates of the “shining city”. Those barbarians were mostly non-white, non-Christian, non-conservative people, all of whom the Klan despised. He (or his speech writers, partially at his direction) frequently fabricated horrific accounts of crimes perpetrated by those groups, and patently lied about crime statistics at times to try to sway public opinion in favour of some of his more draconian policy goals, most of which targeted non-white people for incarceration.
You are right that Trump has used a much more direct and bombastic (and most often nonsensical) approach with his rhetoric of “catastrophe”, but although Reagan’s was far more subtle and refined, it was equally dark in its own way. And it cast the bell for Trump’s rhetoric ringing true to that “gaslit” subset—many of Trump’s most ardent supporters now revere Reagan and were primed to respond to his messaging with the same dog whistle phrases and demonstrably false claims from Reagan.
I definitely encourage anyone that wants a better understanding of these parallels to listen to some of Reagan’s campaign speeches, and later pressers and releases in office. It is striking how much of the language Trump uses is repurposed from Reagan (intentionally or not). It makes sense, though, given the overlap of support—much of his audience responds to that language because they responded when Reagan said it (his 60+ were cutting their teeth politically with Reagan’s rise), so there is a feedback loop leading to more of that language.