I have not heard a R2R 7 but as I said if it only sounds as good as a S7 it will be already great (meaning that the r2r module can compete with a notorious factory chip). It seems that it sounds even better so that's clearly impressive.
About the listening session I got, I've try both Master 7 stock and one with Singularity digital board (a Singxer Su1 feeding them on HDMI i2S, pll off). I was not expecting any difference this way but the result is exactly the difference that you are saying with your r2r vs Master 7 (that's why i said that, no offense intended).
Back to the topic, nobody wants to try the new Schiit Eitr feeding a S7 or a R2R 7
?? I'm very curious of the result, back in the days the Master 7 was clearly better on I2s but with the new digital board perhaps it could compete !!