Great Qobuz streamer. Upgrade from Bluesound Node 2

+1  on the DAC recommendation to pair to the Node2.  I'm doing this on my 2nd system pairing the Node2 to a Benchmark DAC3 ($1500).  I have no desire at this point to upgrade the streamer.

My advice would be to keep the Node and start with a good DAC. My personal favorite is the Chord Qutest, and it should work great with your Node 2. I have had my Qutest paired with a Node 2i. More recently I picked up a Roon Nucleus, and am now using the Nucleus via USB (in my case Curious USB Cable) to the Nucleus .... and simply love it. That combo in its entirety would more than likely bust your budget. But if you take a stepping stone approach, a good DAC would be the very first item on my road map and will give you the best bang for the buck in terms of enhanced SQ.

I'm in the "add a DAC" camp. Streamers are dependant on interfaces and it's likely new music sources will continue to appear. BluOS has a good interface that seems to be flexible. I read a lot of comments about higher end streamers that say something like "It's great, but... (something less than positives about the interface). Streaming is a pretty rapidly evolving space, I'd hate to dump a bunch of money into something that's obsolete in a couple of years or can't play a new service that comes out. DACs are also still evolving, but a really good or great sounding DAC should still sound great years from now. 

I recommend Lumin. We decided to carry them after evaluating the software stack, build quality, and sound character.