My TL/DR opinion is that this is nonsense. Buy the best DAC you can afford. I had a Doge 7 DAC for a number of years, not a bad DAC, but I got tired of the tube output colorations. I borrowed a friend's Chord Mojo and thought it pointed in the direction I was looking for, so I found a used Qutest for $1100. It's a tremendous upgrade for me and fits into my current system very well. Cleaner, quieter, with muuuuuch more information coming through. My listening buddy was over yesterday and was floored at the difference it made in everything we listened to.
I have a $200 DAC in the bedroom system. It isn't remotely comparable to the Qutest.
By the same token, I've heard some very expensive DACs I didn't care for. But by no means is anything over $200 a "waste of money."