I certainly don’t know much about anarchism, but different planets in the federation can and do have different kinds societies.
If we consider the vulcan in brace new world for example, their society seems very much aristocratic for example, where influence gives authority and power. I doubt the klingon are anarchists either. And in lower deck, the orions have a monarchy.
The federation is the government of the collection of planets, but each planet still has its own government and culture.