If I may suggest, it could be that double crown chip. I own the original Orchid for many years now and feel the same as you with your Atlantis. I don't have the budget to try out many dacs like you did but through the years I've never heard anything nicer then the Orchid.
A few years ago there was some talk here about the double crown chip, how great it is... So I thought maybe I could improve my Orchid with one of those chips since mine has the original. Well I don't remember exactly how much I paid for this stupid chip but I ended up re-installing the original chip because it made my Orchid sound less smooth and analog. The other thing is the tubes you tried in your Orchid, the WE396A is the one to use. I tried a multitude of tubes, expensive ones, and nothing beats the WE396A, which also happens to be the preferred listed by MHDT.
Anyway, maybe you could give the Orchid another try!
BTW, thanks for all this info on the different DACs you tried. Every once in a while I have an urge to buy a new dac and reading you comforted me that I can spend my money on other goodies!