I tried this out too, using the Virtual Audio Cable and Voicemeeter. It seemed to help initially, but once I got into a dungeon it came back. Thankfully it seemed to kind of 'fix' itself once I got out of combat again, which it didn't used to do without the VAC, but it's still definitely a temporary band-aid that required installing two different drivers/programs and restarting my system and learning how to set it up just to mitigate some of the problem. The echo did seem to go away during some cutscenes, but really only the ones I watched in The Unending Journey. I didn't want to try and see a new one because, you know, it kind of ruins the story and atmosphere to have to listen to that choppy, echo-y audio. I might suck it up and sacrifice another cutscene to the Noise to test it tomorrow though.
I'm also going to try turning down my graphical settings I guess? Though I never had them super high to begin with. And unplugging my gamepad (which I can't play without, since playing NIN on m+kb destroyed my wrists and made me swap to a gamepad in the first place,) but I really hope that information will be used to determine what needs to be fixed on SE's end, not given as a solution if it manages to solve the problem for some people. My biggest fear right now is just that SE did something with Endwalker that ultimately is out of my control without me having to spend plenty of money to fix, and that the problem's going to be marked as "resolved" and I essentially won't be able to play. Nothing in the benchmark made me think there would be this kind of issues, while my computer is a bit older it's still above minimum settings, and the fact that this issue is happening to so many people including people on consoles and on much better machines than me really makes me think it's not an issue I'm able to fix on my end.
If lowering my graphics settings and unplugging my controller and swapping to DX9 and lowering my sound bitrate and Hz and changing my camera listening position all somehow solve the issue... that isn't actually a fix. If that information is sent to the development team and used to make an actual fix that gets patched in, that's great and I'm all for it. But if the solution SE has is to tell people to try things and see what works, and presents that as the entire solution then it's no solution at all.