MC can take an audio stream from an external App in via the WDM Driver, then play it locally with connected DAC/Speakers/whatever.
MC can stream local (or NAS) files to a DLNA Renderer (which I assume is what you mean by a Streamer) and the Renderer can play that stream locally or via DAC/Speakers/whatever.
MC can't take an audio stream from an external App in via the WDM Driver then stream the audio via DLNA to a DLNA Renderer (Streamer).
I don't know the reason, but it can't, and that has been confirmed in the past by JRiver staff. Plus I have tried and the computer said No.
So, if you use an App from Naxos classical music and want to play that to MC, which you then want to stream to your DLNA Renderer, that isn't going to happen.
However...
MC can take some web streams such as "Radio Paradise" and "Radio Swiss Jazz" then stream the audio via DLNA to a DLNA Renderer (Streamer).
This is a bit hit and miss. Typically it needs some special attention from JRiver to make it work, or a specific type of stream. I just tried to add a web resource for Naxos classical music (
https://www.naxos.com/catalogue/item.asp?item_code=8.508004) to test if I could play that to a DLNA Renderer (BubbleUPnP). Nope, it played on the PC and not the DLNA Renderer, bypassing MC completely and just playing from the Chromium browser even though that was inside MC. (I can play tracks on that URL locally on my PC though, through Chrome.) But then, I just tried to get "JRiver Radio" and "Cloudplay" to play to BubbleUPnP, and neither worked, just skipping through tracks. Cloudplay plays fine locally, though JRiver Radio seems to be having some trouble at the moment, it eventually played locally as well.
You may do better if you have a Naxos classical music account and more direct URLs for streaming audio.
TL;DR No, you can't do what you want.