If you lighten up on nutrient's and plant's are already struggling due to deficiencies,,then they will continue to do poorly in my expieriences.
Consider if they are already ODing on nutrients due individual preference/needs more is not better. Which in this tank is more likely the case vs. being deficient.
For example C. grabowski, found in peat bogs in Borneo, while others such as C. pontiderifolia are found in streams with limestone beds - hard alkaline water. One species, C. ciliata is even found in semi brackish water in some areas. Put those three in the same tank push the parameters in favor of any one individual too much, the other two will suffer to some extent.
Survive and thrive are not the same thing.