Great Qobuz streamer. Upgrade from Bluesound Node 2

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.

Teac NT-505.  $2k.

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.

nekoaudio how is the Lumin app with Android devices? I had a Lumin a couple of years ago but couldn’t get the Android app to work very well.  Has it caught up with the Apple app?