WG, Goddess loses her powers in book

[apediuex]

https://novelfull.com/nightfall.html

Chinese Webnovel (English translation) has some. The goddess of the world comes down to earth, and inadvertently starts to gain weight as she gets humanized by the human world. She eventually ends up quite plump and cannot return to heaven as she loses her powers. This is not a random goddess, but the literal creation goddess (the only one)
The more time she spends in the human world, the more power she loses. Goes from omnipotent to normal mortal. Also her church turns on her and attempts to assassinate her in order to replace her.

She ends up marrying the main character, and the story ends with him complaining that she's not losing weight, and he starts looking at other girls.

Story is long though and the downgrade is not the focus, just a major plot point.