Now that I’m done, my anecdotal take is that in-zone CEs have at least slightly better drop rates. I got the overwhelming majority of my atma from those. Interestingly I got zero from the in-zone fates.
I got my last Realgar (orange) in Shaaloani. Two Verdigris (blue-green) from Kozama’uka, and two Orpiment (yellow) from Living Memory. Verdigris was the one with the most stubborn drop rate in zone; got 1 from the only CE that drops it after doing said CE well over 10 times. I got an Orpiment in-zone early on and it never dropped there again! lol