The so-called gods in the history of Great Xia were probably the same as the main character in that movie.
When the times needed it, a certain person would stand out and obtain 'divinity' because of some special personal experience. The 'divinity' here referred to an abstract concept, a special state of mind that was not supernatural in itself.
Thinking about it, the so-called god of Great Xia might have been someone who stood up when the times needed it and when people needed it. He did something that others did not dare to do or could not do, so he was deified in the hearts of the people.
Mortals became gods.
However, the times were still progressing.
The current difficulties might not be the same in the future.
When gods were no longer needed, people would naturally forget about them--because gods were only mortals from the beginning to the end.
Some special mortals.
But God was not completely forgotten.