These problems have much less to do with libertarianism per se than the practical problem of funding a massive welfare state without utilizing a destructive amount of money printing. Milei is walking a tightrope of unwinding this system slowly. The problem is endemic to having a massive welfare state than it is to libertarianism, and it is one reason why libertarians (also, bog standard neoliberals) are critical of having a massive government. When the government has an extremely large balance sheet, so large that its taxation and redistribution schemes are negative sum, it is only a matter of time before the whole thing comes crashing down. That's where the economy was headed before Milei. The collapse was avoided, albiet narrowly, but that doesn't mean everything is suddenly normal again. The road to recovery will be a long one.
To use your car analogy, the previous peronist parties set up a 1000 mile family trip, bought a quarter of the gas, and then when has started running out wrote a bunch of gas IOUs and pretended that the IOUs were a substitute for real gas. The responsibke adult comes in, and is desperately trying to find ways to trade IOUs or anything else that's available for some gas so that the family can survive and get home. That means that the family might even have to skip a meal or two, which is painful in the present. But it's all a sacrifice in service of ensuring the family's survival over actually starving in the desert when they realized IOUs don't power cars.