The darkest power cable I ever tried was a Pangea from Audio Advisor; to the point I had to remove it from my system. Perhaps it would provide the sonics you’re seeking.
I too have a lot of glass in my main listening room - an entire 9.5 ft wall from floor to ceiling, made up of primarily 4 large individual glass panels. I found that I was able to reduce the sonic glare created by the glass by using one Synergistic Research HFT on the center of each of the glass panels. The HFT’s are so small that I’ve never had anyone even notice that they are there. You may want to consider using HFT’s throughout your room too, assuming your wife agrees that they really are inconspicuous. I have found that they are no substitute for bass traps (which I use as well) but they do help in dispersion and mitigating some of the undesirable reflective frequencies are certain materials. I find HFT’s are best used in conjunction with conventional room treatments and not as a standalone product. But they work great with with the glass in my case.
I too have a lot of glass in my main listening room - an entire 9.5 ft wall from floor to ceiling, made up of primarily 4 large individual glass panels. I found that I was able to reduce the sonic glare created by the glass by using one Synergistic Research HFT on the center of each of the glass panels. The HFT’s are so small that I’ve never had anyone even notice that they are there. You may want to consider using HFT’s throughout your room too, assuming your wife agrees that they really are inconspicuous. I have found that they are no substitute for bass traps (which I use as well) but they do help in dispersion and mitigating some of the undesirable reflective frequencies are certain materials. I find HFT’s are best used in conjunction with conventional room treatments and not as a standalone product. But they work great with with the glass in my case.