@lalitk, thank you for taking the time to reply, much appreciated.
I'm sure I'll keep the Zen stack for at least six months, probably longer. Do you have any particular LPS's in mind to recommend that can power the Stream and DAC?
I'm aware that power supplies are a whole different rabbit hole of potentially infinite tweaking!
As an experiment today I have taken Ethernet out of the equation entirely and enabled Wi-Fi on the Zen Stream. I do have a fairly good Wi-Fi setup in the house and it's usually performant and reliable. What I have noticed is that the sound quality is absolutely flawless, the bass is strong, the vocals are clear and well-defined, the sound stage is wide and the silent moments on acoustic tracks are completely silent. I'm now wondering whether this might be the way to go as Wi-Fi itself has no interference. I could potentially further upgrade the Wi-Fi mesh and feed it properly with good power and who knows?