As far as I can see, I will connect the N 03T, with a USB cable, to my Esoteric K 03XD, and use it as a DAC. In preparation for the (by now highly anticipated) arrival of the N 03T, I bought a NUC with the necessary Roon software installed on it. The NUC (rather similar to the Roon Nucleus) and the N 03T will both be connected to the ethernet switch.
I have the Roon app on my iPad, so I will be able to do Roonish things once the streamer is here. I don't see any reason why I would not be able to install the Esoteric Soundstream app on the iPad as well, in case I want to bypass Roon for some reason, and use it to stream straight to the N 03T.
It may well be that someone who actually has done these things, rather than merely thought about them, has better advice.
Best of luck.