So far, outside of a classroom, the only “Libertarians” I’ve seen in real life are people who vote republiQan and refuse to take accountability for it.

Or people who don’t vote, and allow republiQans to rule while taking no accountability for it.

So, they don’t support universal healthcare because republiQans don’t, and that’s what they really are.

This is the problem with "ism"s. At whatever point you decide that philosophy X is the answer to everything, you start being wrong about a lot of the world, because whatever it is, there's at least like 30% of situations (and potentially a lot more) that your particular ism actually isn't the answer to.

Libertarianism or anti-imperialism or ACAB or socialism or pro-the-Democrats or anarchist or whatever it is, it's never always the answer. Trying to hold a debate about, well is it philosophy X or philosophy Y that's always right about everything, or any other discussion that feeds into the basic wrong premise, is just compounding the imaginary non-situation-dependent way of looking at it.

Although yes some of them are wrong a lot more of the time than some others.

When you combine "Libertarian" with the greed that is typical in the ultra wealthy, their core value typically only includes liberty for themselves and no empathy for others. You can use any party label you want but without empathy, members of every party are nothing more than selfish pieces of shit. Just to be clear, I am not a "they're all the same" idiot, as Republicans clearly think empathy is a four letter word. But there are sociopaths without empathy everywhere in society, especially in the US.

As far as universal healthcare is concerned, we can't even agree as a society to provide clean water to our population by removing leaded pipes. Why would we expect something as reasonable as universal healthcare?

Wanna be free to stay unwell.

On a political spectrum, the term libertarian should relate to anti-authoritarian. So, I can see how the case can be made against socialized healthcare for them. It's not really about true freedom or liberty. And in the US anyway, it's largely just facade co-opted by the ~~fascist~~ [authoritarian and wealthy] right wing, ironically.

The word "Libertarian" in US has less relation to the dictionary definition than "Republican" and "Democrat". These are names of parties over here, even if they have a namesake of governmental mechanisms.

Examples:

Ron Johnson said in a single breath that he was a libertarian and opposed the legalization of marijuana.

Find the average "libertarian" policy position on border policies.

US politics is unfortunately entrenched in tribalism rather than searching for the right tool to match a job or solve a problem and maximize outcomes, the libertarians over here are no exception.

Libertarians usually define liberty narrowly as "freedom from government".
Freedom does not mean the ability to do as you please, but rather the ability to not be told what not to do, or to be made to do something you do not wish to do.
A libertarian usually does not object to wage slavery, and would disagree with the concept of wage slavery entirely, on the grounds that you were not forced to work a job you dislike, since you could always choose to starve instead.

What you're looking for is one of the schools of anarchism.
Although usually painted as "anti-government, anti-society", it actually derives from being against hierarchy, and is characterized generally (there are many schools) as being opposed to involuntary power hierarchies.
Sometimes government is the best way to reduce the total amount of coercion in the system, since forcing a lot of people to pay a little can free many, many people from being forced to do stuff they loath to survive.

Libertarians aren't pro-liberty they're anti-government, and anarchists aren't pro-chaos they're anti-coercian. They're both entire political schools of thought, so I've obviously not encapsulated them entirely in two paragraphs.

Do you mean ancaps? Because I'm pretty sure most libertarian would be for universal healthcare. I have heard Americans use libertarian for ancap which are pretty opposing ideologies, I'm not sure what's up with that.