Exactly, that’s why the UPnP Bridge is the way to go.
The Bridge just converts the ‘pushed’ stream from the Roon Core, and converts it to UPnP frames/packets, as if it is being served by a UPnP Server - the Render, Control App & Server effectively ‘pull’ the files from the source.
So you maintain all the attributes of your Naim Network player, in terms of ethernet based playback.
You can also set the UPnP Bridge for WAV output, and without the FLAC compression flag set in Roon, it will serve uncompress WAV from FLAC/ALAC/AAC & MP3 files for all formats up to 24/192. Set the ‘DSD over PCM 1.0 (DoP)’ setting for DSD playback strategy and DSF files will play as DSD64.
For me, on my NDS/555DR, this is then as good as that played through the UPnP server, where I have transcoding to WAV for all Compressed lossless and lossy formats and pass through for DSF as DSD64.
This is better than a USB out and an S/PDIF conversion, which has the potential to introduce jitter into the process, although I read that the DigiOne board is one of the best and DietPi is easy to setup and maintain.
If you go down the Sonore UPnP Bridge route, just make sure that the Sonore product is running the latest 2.5 OS and has the latest version of the Bridge 1.0.14 - earlier versions seemed to have some problems, with the playback configuration described above.