The essay is just bad. Its answer to "How important were the Achaemenids as a template for Sasanian power?" is "very important" and proceeds to squeeze that from the analysis at any costs. There is no nuance, no balance, just hammering on the point that it was very important.

Take this passage for example:

"The importance of the Achaemenid model for Sasanian power was profound yet selective, manifesting most clearly in royal ideology, administrative structures, and religious policy, while being mediated through the complex filters of historical memory, practical necessity, and contemporary innovation."

This is nonsense. "Profound yet selective" what does that even mean? Was it profound or selective?

Another problematic passage:

"Ardashir's son Shapur I's Res Gestae (ŠKZ) explicitly invokes the memory of past Iranian greatness, presenting the Sasanian dynasty as restoring a glory that had been diminished under Parthian rule."

It most certainly does not. There is no such claim to "restoring" something the Parthian rule had "diminished".

As usual, LLMs can write very convincing nonsense if you don't or can't scrutinize.

This is bad historical analysis dressed up as a pompous essay that looks knowledgeable to the lay person.