I am not sure if DoP is considered as native DSD. WIth the Microsoft's driver, I can still play DSD with DoP. In that case, the DAC would still be able to get the DSD data stream natively (but packed in PCM packet) and it will decode the DSD data directly without converting it to PCM. There is no difference betwee DoP or "Native DSD" over ASIO in terms of the data the DAC received. The only difference is that it needs a higher bandwith to transfer DSD data over DoP.
The support of 768kHz sampling does help to support the DSD256 over DoP. With 386kHz, it would only be able to support DSD128 (over DoP).
On the SMSL website (
M300 SE (smsl-audio.com)), they expliclity mentioned that the DAC supports 768kHz without downsampling (shown in one of the pictures)... I hope they really do support it as one of the major reason for me to get the M300SE is to play 768kHz audio (that I upsample with HQPlayer / PGGB-rt).