Both are a false consciousness that, as such, function to obscure class antagonism and support the capitalist order. They are a form of liberal following a slightly different set of high priests than the others, though obviously they are not separate. While many liberals laugh at, for example, Austrian School economists, they do so while incorporating the ideas from that school that fit the current canon. All it takes is laundering them through other economists.

A Marxist analysis will look at the material basis for these ideologies. They are basically the same as for liberalism - they reinforce a substantial portion of the ruling class's interests. The obvious one is that when the ruling class is interested in cutting its own taxes or regulations, this ideology is very useful. Though it really goes much farther than this: both are cults of capital in the extreme, justifying all capitalist actions as inherently just and all transgressions against them as inherently unjust. Consequently, they can be leveraged for anything that capitalists want except for maybe government grift. If a capitalist lobbying group wants a policy change they can push a "right libertarian" that wants it, easily. If a capitalist lobbying group doesn't want a policy that threatens their interests, they can fund, say, the Cato institute to tell you some bullshit about how it's bad according to their economic religion. It's not fundamentally different from how capitalists fund others members of the political class.

To the extent that it is different is that it is more extreme. It's a wrecking ball that competes with the interests of other capitalists that benefit from various government policies. So long as there's a "big government" means by which to increase profit, there will be a fight.

On the personal psychological level there is plenty to discuss but I think the false consciousness is the most important aspect. "Right libertarians" get to pretend to be an outsider political trend, even one opposed to the status quo, and openly recognize various problems in the capitalist system. For example, they get to be vaguely anti-war, at least rhetorically. And they usually try to wash their hands of the decisions made by Democrats and Republicans. Then they go and reinforce the dominant capitalist system. In this sense they are very similar to radlib socdems, just with a different aesthetic for what it means to be an "outsider".

In my experience, if you can get a right libertarian to actually read socialist theory they can actually be pipelined. Nowhere near 100% rate but better than your average lib. They will be annoying the whole time, though.