Actually, overall, it's not too difficult.
Divine Civilization is an ancient concept.
So ancient that when the Federation said gods had emerged, Federation Citizens didn't think this had anything to do with the Divine Civilization. They thought it was a resurrection of gods from myths. Rumors even spread about the resurgence of Spiritual Qi, implying that everyone would soon become immortals.
After all, the vast majority of Federation Citizens had absolutely no idea about the Divine Civilization.
It was not long ago that the Federation discovered the existence of the Divine Civilization from an archeological site.
After all, there's a complete disconnection between the two civilizations.
No one knows whether the Divine Civilization is tens of thousands, hundreds of thousands, or even millions of years older than the federal civilization, or if there were other civilizations between the two.
This is absolutely unknown.