I believe at the beginning of the story that you could use the source energy to increase your affinity for that element. Wouldn’t it be better to increase your affinity for the elements first so that it is easier to manipulate later.
Hope you get better soon. You should add some of the goddess to the harem like Athena, Aphrodite, Artemis, Iris, Persephone, or Hecate. You can add other goddess from other pantheon too. I just know about the greeks.
Here is a thought. If you add Zhuqing, you can have her spirit become more dark then speed. So she wold focus on the darkness element instead. Basically becoming an assassin.