Although there was a brief discussion of >20khz response, the OP has repeatedly prioritized a "fuller, warmer sound". This sounds to me like the mid-range.
The original holder of the MC patent was audio legend Joe Grado. However, he didn't make them. A believer in the importance of getting the mid-range right, his cartridges were MI (Moving Iron). AFAIK, Grado & Soundsmith are the major MI cartridge makers today.
The Schiit Mani 2 gives you plenty of versatility for optimizing your phono sound, and should result in meaningful improvement. Upgrading your cartridge will cost more, but should also make a bigger difference in the sound.