It's not the RNG, its the implementation of the system

[Fawkes]

Note: You can also get each type of demiatma from each of the 6 DT zones. For me, I never got around to maxing out the FATE levels when DT first released, so I'm just doing that now. Doing exactly what you mentioned - chipping away at the "large" number of FATEs required in each zone while simultaneously picking up the demiatma I need along the way.

I feel like getting them in OC or from Dawntrail FATEs are supposed to be two different ways for different types of people, but the way it's implemented even if you just want to do the new content you should get as many as you can stand in OC and then do FATEs to finish because it sucks getting specific things in OC. The FATEs are more of a band-aid than an alternate acquisition method.

It also didn't help me as I had already finished FATEs for the zones I needed atmas from but I still need some FATEs from other zones.