My advice is still to remove the PC from the equation and only make sure that your audio streamer (remote controlled)  is fed with the cleanest power and ethernet signal possible into the DAC. That is all that matters in my mind.

I can see all sorts issues trying to handle a fluctuation in noise floor from an involved PC when we are at this crazy level of noise reduction. 🙂

In my situation I use a Jcat which has a galvanic isolation to the PC's powersupply. It uses an external powersupply. Which is a Farad in my situation.

Beside this. Still after 5 years. I would be the only one that has problems with these streamers. I also think I'm probably the only one with a very clean powernet, has a dedicated network for audio and upgraded each an every powersupply on the network

Wifi is not possible for me. I think I should stick with the current situation that works. It's still on an incredible level. Really on top streamer levels. There seem to be limits in one of the parameters. I think it's the clock banging.

One more note.

Roon chose this track to play

Watching the Waves (Acoustic Version) from David Gray.

The Album GOld in a Brass Age (Ground Control Acoustic Sessions)

The singer has an incredibly clear and natural voice. It's just an internet stream

Yes, but roon is fairly process heavy since it sends more metadata. Many streamers sound worse with roon then their native qobuz interface because roon makes the CPU in the streamer work just a little bit harder.

These differences is mostly heard when you have a very low noise floor in your streamer.

Grimm audio is roon only, and amazing, but they have obsessed in making sure that the CPU noise does not impact the DAC clock.