Streamer's without built in DAC options?

LDMS. Amazing piece of kit. You can spec it how you like. Best sounding streamer out there
https://www.lucasaudiolab.com/about/

McIntosh MB 50. Lots of streaming sourceboptions. I run it through my C 48 preamp. Balanced, unbalanced and digital connection options. Under the radar in my opinion. 

One recommendation, whatever you end up with will benefit further by removing the RFI mixed in with the Ethernet signal going into it. Network Acoustics ENO filter works wonders.

I have used a pro-ject stream box s2 ultra for a few years, and it works very well, and sounds a bit nicer than feeding my DAC direct from a Roon NUC.

I suppose one scenario in which you might want to add a streamer without a DAC is if you want your Nucleus to be in a separate room, and you want to use the Tambaqui as a USB DAC (instead of connecting it by ethernet). In that case, you might consider one of the Sonore Rendu products (such as the ultraRendu).  That's assuming you don't need the device to support, separately from Roon, a streaming service such as  Tidal.