Libertarians are not against parks, schools, libraries, defense, quality control, etc.
Libertarians to different degrees are against the state providing them through tax funding.
Libertarians are also skeptical that the state can run any of these things effectively which can be illustrated by endless examples of the state providing something versus non-state actors. (Google when government provided cellphones)
You can have schools, parks and libraries that are open to the public without them having them to be run by the state or funded by taxation. We can find creative ways to provide these services (user fees with sliding scales, subscriptions, bundling, sponsorships, donations of land/resources/Money, tokenization) for everyone’s use that are lower cost and better run, it just requires experimentation and imagination.
That’s what libertarians want, not to eliminate the ability for services and goods people want to be provided but to take it out of the realm of the state so individuals and communities can discover better ways to fund and run them that involve their buy-in, their consent.
Libertarians want the accountability, the efficiency and value that consent brings to all aspect of our lives where we let it.