@hudsonhawk You are right that most (delta sigma) chip based solutions would converge pcm/DSD to a single bitstream at some point internally. And you are right that at the end of they day it's more about overall execution than technology. I used to be a stickler for the purity of R2R (chip or discrete ladder) but have since realized that there is more to it than that.
That said, there are some R2R dacs with separate paths for PCM vs native DSD that might meet the OP's goals. Lampi became first known with their dedicated DSD R2R dacs I believe. Some of the Denafrips R2R ladder Dacs do both PCM and DSD. And the Holo Dacs most definitely have separate R2R ladder circuits for PCM vs DSD. I think this is one of their perceived values. And they allow for OS vs NOS modes as well - most prefer NOS. A discrete NOS R2R ladder DSD process would be as close to the pure DSD playback the OP is looking for. The new Holo May looks intriguing but starts at $3800.
That said, there are some R2R dacs with separate paths for PCM vs native DSD that might meet the OP's goals. Lampi became first known with their dedicated DSD R2R dacs I believe. Some of the Denafrips R2R ladder Dacs do both PCM and DSD. And the Holo Dacs most definitely have separate R2R ladder circuits for PCM vs DSD. I think this is one of their perceived values. And they allow for OS vs NOS modes as well - most prefer NOS. A discrete NOS R2R ladder DSD process would be as close to the pure DSD playback the OP is looking for. The new Holo May looks intriguing but starts at $3800.