UPDATE 2
My noise free experiment I thought was working came to an end. I had white noise again.
Now, I went back to my initial setup of a Mac connected my DAC with a USB cable. This setup has been noise free for about 10 days now, although it hasn’t worked in the past.
As an update, I changed my Roon core from an iMac to a dedicated Mac Mini M1 with a short USB cable to the DAC. After a day or two, I got the white noise again on a DSD64 album in my library (DoP 256)
Then I decided to change players. I closed Roon and played the same album with JRiver and the noise was still there.
So, I think I’ve tried everything but a Windows PC or a different DAC.
The DAC manufacturer doesn’t have an answer.
Next I will try waving a dead chicken over my head while rubbing my stomach counterclockwise.