@PYP,
Since you no longer (?) mention the use of a switch or clock (and possibly ethernet cables, fibre etc.) in your current signature except for a filter I'm curious if your previous observations still hold true with your current system:
NA Muon Pro > Grimm Audio MU2 > Mola Mola Makua > Mola Mola Kaluga > B&W 803D3
Regardless the quality/provenance of a music file, does sq remain consistent, regardless of whether it is or NOT passed through a (best?) audiophile switch, clock, or any other upstream component before reaching the MU2?
In other words, with your setup, do these devices make a discernible difference in the final sound, or does the music always sound the same?
edit:
Grimm Audio suggests that most noise is effectively suppressed within the streamer/DAC itself, outperforming what upstream devices or combinations of devices can achieve. Apparently this noise suppression occurs in the analog domain (not the digital domain), and is further enhanced by a high-quality power supply.
In this context, when considering the role of the best audiophile network switch, it seems to me that while it might not achieve the same level of noise reduction as a well-designed streamer/DAC, it can still contribute to improved sound quality in other ways however an audiophile switch may not drastically lower noise levels to the extent possible by the server or streamer and it can offer other benefits.