How does the Avatar spell function if my character worships a god that isn’t listed under the spell?

more questions concerning Pathfinder Second Ed, but it’s something that I won’t need the answer to until MUCH later down the road. Right now, I’m about to start a 3rd level campaign centered around upper-class intrigue and pirates, so I figured I’d try playing a Cleric of Ng to fit a setting with implicitly ambiguous morals. However, I’m looking both online and in the physical copy I have of Lost Omens: Gods and Magic and cannot find any mention of what additional benefits you gain for casting the Avatar spell while worshiping this god and its contemporaries in the Eldest Pantheon. In addition, I was ecstatic when I discovered that Grundinnar (the first God I played a Cleric of back in PF1e) was included as a part of the Dwarven Pantheon, but he’s in the same boat as the Eldest since the Avatar spell does not specify either Grundinnar directly or the Dwarven Pantheon in general.

So my question is If a Cleric casts the Avatar Spell and their Deity isn’t listed under its effect, what happens?