Question: Why is the desire the foundation of everything and not the thought?
Answer: Thought is generated from the desire and therefore it is secondary.
Question: As opposed to the world of good, stands the world of evil (emptiness/nonexistence). It turns out that now the main direction is not toward the Creator, but toward emptiness, the destruction of nature and the Creator?
Answer: No, the evil of the world is only so that we will recognize the evil of our nature and begin to ascend to the Creator.