Please do keep us in the loop on your search. My digital side is pretty much an over site on my system, mainly because the learning curve is steep. I just use the DAC on my Esoteric K-03XD (a lovely CD transport, mechanically), and a Lumin U1 streamer. This is actually excellent but room for improvement exists.
FWIW, I’m extremely interested in the Nagra HD DAC X and nearly pulled the trigger just based on my ownership of the Nagra HD preamp, which is shockingly good. I also did a shoot out between the Nagra HD phono and many other phono preamps and it ended up in the top 3, losing out purely on my subjective taste. Long way of saying, I almost bought the DAC unheard just due to experience with other products. I also like the idea of tubes on the digital side for reasons I can’t logically explain.
Id be particularly interested if you get one of the MSB products, the Mola mola, or the Weiss. I will admit I’m not in love with the Weiss chipset. The MSBs get stupid in price and can cost the same as a mid tier Range Rover, but their middle products seem to have most of their features So in my musings, the Mola Mola is the leader, but I’ve literally never heard any of them, except the MSB and it was in a friends house during a party and less than ideal listening circumstances.