Point of diminishing returns for a Network Streamers?

All a streamer really needs to do is transmit the bits from local storage or a music service to your DAC intact. It sounds as if your setup already does this. There’s no need to make a change unless you’re detecting noise / pops / ticks / dropouts during playback.

As a reference, have a listen to the ’Bad cable’ sound sample from this link - What does a bad USB (or other digital audio) cable sound like? This is also what you'd hear from a streamer with suboptimal digital interfaces.

If you’re focused on improving / changing the sound of your system, you’ll get more bang for your buck if you look at different speakers or headphones than electronics IMHO.

@soix 

Why? Educated audiophiles can make better choices on what to spend their hard earned money on - whether that information is objective or subjective. I just happen to like to weight my purchasing decisions more towards facts than opinions.

In any case, I really don't care if someone wants to buy or recommend something if it sounds better to them. I'm just trying to point to actual audible phenomena vis-a-vis typical audiophile claims.