I don't think child markets, sovereign citizen nonsense, and "do we really need an age of consent?" are representative of the Reagan era. Those can be hot-button issues even among conservatives, and they certainly have never been mainstream Republican policy positions.

There is no contradiction between sealing the US border against latin migrants and flying out to the Dominican Republic for underaged sex tourism.

The vast majority of conservatives will agree on immigration, but you'll get divisions on something like underaged sex tourism. See the "uhh I don't remember any of that" interview with Tucker Carlson and Matt Gaetz. Some of this stuff is not palatable in the mainstream.

As for proto-chuds noping out of places, there's no good way to estimate numbers, but some do. Hell, you can find people around here who'll talk about how they went through a libertarian phase, or were straight-up chuds at one point. Also worth considering is that a lot of people are "cultural conservatives" -- they don't really think to much about politics, but they grew up in a Republican household -- and those folks might be split off more easily than someone who's super invested but not especially deep in yet.