There might me more options, but basically I understand the three main measures as “sophisticated” Bridge setup, which I already mentioned briefly:
Measure 1:
Running a separate mains circuit for the stereo setup, so that the rest of the house electricity including router, network switches, NAS drive, PC etc. runs isolated. This means some effort by your house electrician.
Side note (as I understand it): To achieve this isolation of the library processing unit from audio relevant electronics, e.g. the upcoming Octave server among others has to inherit costly technology to achieve this kind of power supply isolation inside the unit.
Measure 2:
Use a galvanic plug in isolation device between LAN cable and Bridge.
Side note: the upcoming Octave server to my understanding will inherit also galvanic isolation technology to avoid noise from LAN connection.
Measure 3:
For a proper comparison with e.g. the DMP, play .aif or .wav files also to the Bridge from your library. Reason is: the DMP also reads such formats from physical discs and not compressed formats like .flac, which need additional processing power of involved hardware and therefore compromises sound (so a theory and experience of some). There are different opinions on this and Ted points out that depending on care taken when comparing, various impacts could lead to differences so he sees this critically as you can read here https://forum.psaudio.com/t/firmware-versions-and-digital-sources/4630/14
IMO it’s easy to try if in your setup there’s a difference, so you can judge yourself. I tried it after an early recommendation of Paul shortly after I bought the DS, heard the difference and sticked to it.
As I see it the remaining main sound quality differences between the various options Bridge, DMP, Music server come from the actual digital lens technology (rather than the varying concept of streaming or physical disc). The latest technology usually wins over the previous. Currently Bridge II is the oldest.