Yeah exactly. And considering clerics are devotees of specific deities it’s not like they’re going to be experts outside of it. As a DM I assume clerics have a firm understanding of their god. You don’t have to roll to know anything I expect an ordained minister to understand about them. But just like I don’t expect a priest of Iuppiter to understand Cybellian rites or Saturnian prayers you’re shit out of luck about questions not relating to your god.

And in that vein basic questions about local religion should have a low dc, but cultural distance can increase it. That priest of Iuppiter may have reason to know about other deities in their region even secret ones, but knowing jack shit about Shiva is academic to them. Knowing anything about Zoroastrianism is on par with knowing history to them. They likely know a bit about Ra and Osiris, but only because those are basic facts about a significant nearby culture’s religion.

All the advantages that being a cleric provides here should be represented in the form of proficiency. But you aren’t studying this shit, you’re deepening your connection to your deity.

That said I do think there’s room for an int based holy caster in something like pf2. A religious scholar rather than cleric