OK thanks, getting clearer in a way, but more confusing to me because I know nothing about the SOtM SM200 
Searching for it, I only find that the old one was a “Roon certified” (as it was called back then) streamer and users of this device run the Roon core on something else like a Windows PC or ROCK on a NUC. E.g., here:
And here is is referred to as “Roon Ready”, i.e., also an endpoint and not a Core:
Or here:
Maybe a stupid question but are you really sure that you are running the Roon Core on that?
I think we need someone who knows about this device, as obviously I am helpless here
For better visibility to knowledgeable people I have edited the title to add [SOtM SM200] and moved the topic to the SOtM area of the forum