Was Tsukiko a godless cleric?

[KorvinStarmast]

Then again, she helped destroy the city that followed all those gods.

It is more correct to say that she helped to conquer a city that followed all of those gods. There are numerous nations/city states in the Southern Continent.

There's a map of the Southern Continent in one of the books ... Realm of the Dragon, Raja kingdom are also entities.

For example, in an analogy, you could say that Paris is the most important city, or the nicest city, in Europe but it isn't the capital of all of Europe. Just of France.

As to the other post, I find it odd that folks are trying to shoehorn the worship of a pantheon into the concept of 'a unified church' and 'a single unified clergy' - I don't think that model fits.
It certainly doesn't work that way up in the North among the dwarves; high priest of Thor and high priest of Odin as two examples however that may not be the best comparison as I am unclear on how the humans and other humanoids up North address their deities/religions/gods/pantheons.