Thanks for the detailed reply and explanation.
For added context, I was searching for those soundstage and depth related differences. I let my normal library of music play throughout an entire day switching back and forth. I was not using specific test tracks.
Also, I did much of my testing with Focal Clears - which are much more resolving than the 6XX. Neither of them are super soundstage kings, so maybe that's a factor. I'm also running everything through a Motu M2, which is not an audiophile DAC, but very neutral and low distortion. I don't believe anything in my system is enough of an outlier to be an outright bottleneck, but I'm sure opinions differ.
Photography is one of my hobbies, and I can very much relate to the depth of field differences you're describing. The thing is, I can easily see the larger bokeh, blur, and facial distortion changes between focal points of lenses.
I've been fascinated by the entire subject around well measuring solid state amps and how they sound. I tried getting the two most different sounding amps as described. One being lean, harsh, soulless, analytical (THX) and the other being soft, rolled off, smooth (Singxer).
At the very least, I will say these claims are highly exaggerated. I find calling the THX amp soulless disingenuous to say the least and a disservice to many getting into this hobby and starting out with a quality product. These differences should be put into context, and hyperbolic terms like "soulless" are not helpful.