Yeah, you have that perfectly backwards. "Might is right" implies the most powerful entity has 'the right' to do what it wants on the basis of the ability to assert it. That it cannot be bound or constrained by rules / laws. And all other conflicts also reduce to "which entity is more powerful". So, by the time you go down the entity list from most to least powerful, there is no room for rule of law to bind any given actor.
You asserted three very distinct claims as equivalent, none of which included authoritarianism.
Authoritarianism is not "might is right". The authority at the top does not extend the 'right' of might to agents in the middle of the hierarchy. They are bound by the authority's will in their behavior towards their own power-inferiors.
And hence it is anarchy.