Empress Nuwa was indeed weary of the life of a Saint, constantly restricted, even when she wanted to help the Human Race, she had to do it in secret.
Now that there's an opportunity to free herself from the constraints of the sacred position, she naturally wouldn't refuse.
Fuxi can reincarnate as the human Fuxi, so naturally, Nuwa can also reincarnate as the human Nuwa. Or rather, the human Nuwa has always been there, as Fuxi's wife, which is the incarnation of Empress Nuwa.
Now, Empress Nuwa is merely replacing the incarnation with her true form.
As for Empress Nuwa's original identity, to save the Prehistoric World, she dispersed all her Original Source, fulfilling from start to finish.
Although Saints have many faults, no matter how you look at it, Empress Nuwa is the one with the fewest blemishes among the Saints. Since she became a Saint, her actions have been entirely different from other Saints.