So you all got me interested in Grimm again and I reached out to them and asked whether they were considering developing a streamer type product. John-Paul Lizars replied that their goal of the MU1/MU2 was to offer "a self contained solution to digital audio playback." They strive for "the best possible fidelity, an elegant simplicity and user friendly operation." Of the separate server and streamer set-up, he said, "the use you describe, while having merit, is more complex than we like." However, he also mentioned, "the MU1 can function as a Roon endpoint and customers do use it that way to accomplish the configuration you describe."
Subsequent to that, I found and purchased a Sonore Signature Rendu SE Optical from a seller who is only about an hour from me. I like the simplicity of the Sonore streamer and if the sonics match the reviews, it should work fine for me. If not, there is always Grimm.