Honestly, I don't think you are helping your case here. You are asserting a lot of sound differences that are not readily identified or absent in electronics. I doubt, for instance, that you could identify MQA in a blind test (of music, not over-amplified residual noise). Not because I know anything about you, but because it is just very unlikely based on experience to-date. Soundstage is going to be dominated by room effects and speaker dispersion (presuming decent channel balance and flat FR, which is easily achieved in electronics).For instance "sound stage" is a vague term that can mean many things, but it is still useful. On different equipment (and even different volumes) the positioning of an instrument in my room can sound further to the side of a speaker or more forward. You can say its nonsense because you can't directly relate it to a frequency graph, but it is describing how the mind perceives the sound.
If you hear the MQA stuff it tends to really float around the room, I'm told there is some sort of phase shift due to non-linear filters. Using terms like it sounds like phase shift is meaningless, explaining how it impacts the sound you perceive is more useful to understanding what that sounds like. Q sound if I recall from a long time ago also played with time alignment stuff and had a similar sort of tripiness. Anyway terms like soundstage and positioning of instruments in the soundstage are not nonsense, in some sense they are talking more about the actual experience of the sound.
At any rate, the usefulness of audiophile technology has been argued to a standstill in these pages. For the most part, when you can directly connect a measurable phenomenon with the term, it can be a useful shorthand with others who share that specific knowledge (as 'honky' and "shouty' typically describe specific frequency emphasis). Outside of that, as you say, they are "vague terms that can mean many things".