Hi Toki; Welcome to Permies!
We have raised cats for the last 20 years so I understand your frustration.
I don't think that D.E. is the right
answer although it sure won't hurt.
We clean with a product called Natures Miracle, it works for us and is readily available. It does have a fragrance though so it may not work for you.
Another cleaner we use is a combination of warm
water ,vinegar, washing soda & dawn. This works amazingly well for general cleaning. 1 cup vinegar,1 cup washing soda and 1 teaspoon of Dawn. We regularly cut that back to 1/2 cups .
Try the Natures Miracle they claim it will even remove it from subfloors.
Good Luck