I think you underestimate the complexity of the right. It is not just secular nationalists all the way down.

First, there are still religious people there, and this very wing is splintered among several groups at least. Famously, many Catholics including JDVance were in a value conflict with their own late Pope Francis. The actual religiously educated people tend to be very good at writing, because the schools that they graduated from are good at teaching persuasion.

Second, there are libertarians, not very numerous but somewhat influential, especially in tech circles.

Then, there still are some trigger-happy neocons, nowadays marginalized, but they may yet come to the fore in case of a bigger war that directly involves the US.

Then, there are reactionary types like Curtis Yarvin, who dismiss any nationalist ideas as blind alley of "demotism".

Even the practical question of "how many people from which country should get a visa yearly and under what conditions" will hit enormous ideological differences in the right-wing tent.

To me, religious people, simple racist and libertarians all suffer from a identity-based cognitive bias. "Our groups or my well being is the ideal to project onto the nation/world." (Neocons dont fit in here, i have to admit. Maybe its abuse of power pleasing the monkey brain, but resulting wealth certainly too.)

I think self-withdrawal is more frequent in left leaning individuals for this exact, more unbiased/intelligent/educated reason.

But you are correct again. There is a lot of complexity on the right, if you look deep enough. But this depth does not cause as much infighting compared to the left, because, again: tribalism taking over higher order reasoning.