Also, I really don't buy the everything is below audible threshold levels stuff... using some fairly nice Infinity Kappa 9 speakers when I first started into this stuff, which have ribbon tweeters and super tweeters, there was just something off and cold about an amp that I had been suggested to pursue and use. The Adcom GFA555 II, which has tons of power for the load, handles low impedance loads such as the Kappa 9s just fine and has low distortion. I was never quite happy with the presentation despite everyone and everything pointing to a match... and while I don't have charts of it or the other amp that replaced the Adcom (a Yamaha PC2002M) I do know what my ears and body felt with the new presentation, the texture of the sound. A sense of grating on the ears from the treble was gone, a slightly but significantly lesser degree of that coldness. Similar specs, similar price, different seat of the pants results; which many, especially on r/headphones at least for headamps insist is all in the head. Really don't think so with as many amps and receivers and all, that have been in different configurations as a major hobby for a decade or so with not much thought about what as much as about sound and feeling.
Of course tubes often exhibit great warmth more readily than solid state, I have definitely heard in those two examples a with a subtly cooler and warmer leaning SS amp with not super high THD numbers of 0.007 or so, not to an extreme but to a slight tilt... and even those with a little bit higher numbers like 0.05% can sound incredibly clear in something like a Yamaha CR-1020 vs a MAC 1900 with 0.2% or SX-939 with 0.3%, being a bit warmer still, which is much higher but not really wooly or anything. If those numbers had different orders and ratios they could be tuned differently than warm leaning profiles.
IDK, maybe I'm rambling my ass off, but this is what I've experienced. Similar values can be different in presentation, due to those subtle factors which a simple number value doesn't really do justice to.