It appears you can play DSD via DoP (DSD over PCM) via Ethernet
You are playing DSD files when the DAC is extracting the DSDxxx file from a DoP file… The DSDxxx file that is transmitted using the DoP PCM carrier sample-rate, and played by the DAC, is native DSDxxx 1-bit data that has been embedded in the DoP PCM carrier and extracted as a pure 1-bit DSDxxx signal that is presented to the output circuit of your DAC… In the case of DoP 1.1 as supported by Audirvana, you can play up to DSD256 (11.2MHZ) files and it’s DoP PCM carrier sample-rate will be 24/705.6kHz.
Try playing a DSD128 track with DoP 1.1 enabled and see what your DAC displays… Based on what you told us, regarding the DSD64 track, It should show as playing at 24/352.8kHz which is the DoP carrier sample-rate for DSD128 (5.6MHz)
The DoP PCM data-stream is just a transporter of the native 1-bit DSDxxx signal sample-rate to the DAC… Alternatively, In the case of your USB connection, DSDxx is transported as raw 1-bit DSDxxx signal to the DAC, on Windows based machines running Audirvana… On Apple macOS machines DSD is transmitted via DoP.
