I had a similar quandary in the past in a tube amp trying to bypass the "evil(?)" Alps Blue velvet. Used the amp with the pot just bypassed completely. Later, Alps was changed to better-reputed TKD for sources that needed volume control. These days, I mostly use the TKD with volume open all the way to "effectively" bypass it.
To be honest, I wouldn't want to bet any amount of money I could consistently identify sound quality differences in blind testing, in any mode above. 😥