I’ve known a bunch of them and I think their ideology is fine on the surface, but full of small contraddictions, for example:

• they believe freedom is the utmost important thing, but their freedom is always threatened so they always should do what they do want, even if that limits other people freedom. For example: I should not be forced to pay taxes if I don’t want because noone should be forced to pay for a “service”, it should always be a choice (but if my country gives me healthcare without paying taxes, I should also use the service). However, things like paying tolls for private highway is also bad, because one should be able to go wherever they want withou paying. See the problem in this?
• they don’t believe in “rights” as anything imposed from the top is bad. If a category is persecuted (black people, gays, whatever) they should not be protected, but fight on their own
• according to them, in true capitalism, free market is perfect and the most just, and monopolies will not happen on free market. Now they happen only because laws allow them to “manipulate” the narket.
• they often spiral down alt-right conspiracies theory with a libertarian flavour, like a deep-state working hard to limit even more your freedom, or everything even remotely “politically correct” (even things like protection against protection against being fired because you are homosexual) is woke propaganda and also aimed to limit your freedom.

That’s my experience with a few tens of people, so I don’t know if that’s representative of the whole community, bu my own little consipracy theory is that libertarianism as I know it was crafted by the US alt-right to subtly manipulate people into fascism, the premises are all there: hatred for the current state, bigotry, extreme victimism, a willingness to strip down thenselves of hard-fought rights and a hustle/grinding mentality to slave yourself down to work and enrich other people