Hi Jorge,
I just came across this again. This issue was addressed in release 2022.08. MemoryPkg now supports data words of any width. A couple of different implementations of MemoryPkg are provided via generic instances). The instance MemoryPkg (and MemoryPkg_X) stores data and X/U’s. The instance MemoryPkg_NoX stores only data and X’s are mapped to 0.