Basically, conservatives got increasingly angry (because things inevitably do change), so they decided to give up on conservatism and flip the table instead. One intellectual upstream of Trumpism is the writings of Mencius Moldbug (Curtis Yarvin), who laid out how mere conservatism wasn't enough because "Cthulhu swims left" still, and coined his philosophy "reactionary". This also ties into one of the commonly-described dynamics of fascism - invoking an idea of some imagined idyllic past, as a reason that the current society needs to be attacked and destroyed.
I had never voted for a major party candidate in a national election until Biden 2020 and Harris 2024. I consider those solidly actually-conservative votes, and partially attribute them to my getting older and more actually-conservative.
I grew up [second hand] listening to a lot of this, and as I came of age I could never understood why there was so much cynical condemnation of the system but yet the cognitive dissonance to keep voting for more of the system. But I guess farming this dissonant frustration was just the whole point. Another way of looking at it is that Trumpism is this populist monster escaping, devouring the Party traditionalists, and leaving Republicans with nothing but Trump.
In some sense I think that is large part of what's fueling the fascist energy is the fact that Trump is not a [traditional] Republican, a conservative, a moral person, a competent businessman, etc. So throwing your support behind him is already buying into a Big Lie where up is down, there are no values or morals, just purely allegiance to what Dear Leader has declared is true. That none of Trump's policy positions make sense is a feature for keeping that support in line - independent thinkers who would point out the contradictions are ostracized and othered. Essentially the worst social dynamics of "woke" most everyone was wary of, but we had/have forgotten how much worse they can be when power is wielded autocratically rather than bureaucratically.