My own experiential conclusion is that chasing the “perfect” HAs settings is most likely a no-win situation. Acoustic landscapes are very dynamic even one on one and whether person is articulating or slightly turning their head and the frequency structure of what they are saying AND how familiar I am with the topic we are discussing and what they might typically be conveying. For me there is a range of settings that seems to be perhaps?? good enough; meaning that they are optimal for moment “X” and less so for moment “Y” whereas for some other choice of settings that might be reversed. Of course we hope for the magic bullet that is a sweet spot for a very wide range of moments.
I have shifted my hearing strategy to continue to include the vital importance of my HAs and to perhaps every 6-8 months wondering about changes in settings based on primarily objective testing of my hearing, but in between time focus on what I can do from moment “X” to moment “Y” to improve the communication. As with my eyesight, letting go of too much efforting and straining to hear and understand tends to improve things along with focused attention on what is coming through clearly (as if I am telling my brain “thank you for that clarity, would love more of that”). Don’t get me wrong, I still have frustrations with hearing and HAs and ask for things to be repeated etc. but somehow softening my attitude toward what I experience has me happier about my communications. Sometimes when hearing every word accurately is not an issue e.g. I am not following instructions, giving some attention to the feeling being expressed create more of a connection with someone than decoding clearly each word. All of this is easier with those whom I am close to rather than newly met people and there is a clarity threshold below which I find that I have almost completely lost the person, yet allowing what I hear clearly be somewhat dynamic is often ok. Sometimes I move into a mode of hearing someone as if I am listening to music and allow my attention to shift to different aspects of the “vocal instrument.”
Seems like from what you wrote, you have good self observation on what hearing is and isn’t working for you … hope you find the sweet spots as you go forward.
Edit PS my comment has moved this thread far off from what the OP started with; my apologies.