Notice that the two examples of reasonably stable anarchic societies, Saga period Iceland and Judges Israel, were oppressively theocratic.
In Saga Period Iceland, if you need help to enforce the law, the posse leader was a priest. If your law enforcement was disputed, your lawyer was probably a priest, your opponent’s lawyer was probably a priest, and the judge was a priest.
Saga period iceland was anarchic because their religion demanded that a manly man himself enforce the law when wronged, thus rejecting a special role for the state. But it was cohesive, because everyone in power was supposed to subscribe to the official religion.