What's "Lielbertarian" and why does searching for that give me zero results? Is it a typo?
If by "Lielbertarian" you mean the same thing I mean by "Libertarian with a capital L" (and what I mean by that is the U.S. Libertarian Party), then identifying as a "relatively centrist Geoist Minarchist Libertarian" explains why you'd say that "Libertarians are by definition anti authoritarian".
To a left libertarian (with a lower case l), right-wing "libertarians" (in quotes on purpose) simply prefer to be subjugated by despotic CEOs and landlords employing privately-owned mercenary paramilitary/cop organizations (like the Pinkertons) over being subjugated by despotic tyrants wielding state police and military. They're "libertarians" in name only. So long as my boss holds the authority to deny me access to the fulfillment of my basic needs and uses that authority to coerce me into creating surplus profit for them, nobody who thinks that's ok qualifies in my book as "anti authoritarian". (And no, the right to choose your own master by changing employers doesn't change whether it's authoritarian or not.)