I think the obsession with AC connectors and power cables is pretty funny. I mean, at some point you have to realize that even if you could learn to hear these differences, is that your goal? To die saying you can hear a difference between the use of different AC outlets, or do you want to say you heard a lot of great music?
From a practical matter, I do think minimizing the noise equipment gets from the AC is important, but how much noise you have, and how well your gear filters it out already is quite variable.
On top of that, a lot of outlets and cable will make things worse by making noise easier to infiltrate your gear.
My usual advice is: Keep your digital wall adapters outside of your clean power conditioned power. Use high current, high filtering power conditioners like the Furman units with LiFT and SMP or power regenerators like the PS Audio units, and be done with it. If your outlets are old or loose, replace them with decent new units. https://amzn.to/2TIIc1i