spend on the streamer or on the DAC ?

I have a different view than the others.  Yes, the DAC is very important, but I also found that the streamer or source is as important. 

I started with a Node 2 going into an outboard DAC, and found a sizable improvement in performance when upgrading the streamer going into the same DAC.  BTW - It didn’t present itself as a tonal difference, but In the form of a lot more spatial detail.  The Node 2 sounded “flat” dimensionally in comparison. The upgraded streamer also offered more information and musical detail but the most obvious difference was how the soundscape just opened up dramatically.  

Perhaps you could audition better sources along with better DACs to see how it works in your system. In any case, YMMV but it’s worth exploring.

My $.02. 

My own experience with chasing dacs to focus more so on the source , it was the source that clearly more satisfying results .

First, I'd advise laying out something of a roadmap, and budgeting for the potential additional pieces, including cables . Are you currently doing Roon?  Is that something that you wish to consider?  Apart from a DAC, would a Roon Nucleus or some other Music Server make sense.   With a 5000 Euro budget, there is an awful lot that is available to you with that type of spend.  All things being equal, I'd start with the DAC, continue to use the Node 2 as your streamer, and go from there.  That being said, would still advise taking it step by step, seeing what you have with each new piece added to the puzzle. If you have a trusted dealer you can work with, all the better.  Take your time and enjoy the journey. 

+1, mgrif104.

Node 2i is and will be a average sounding device even with an upgraded DAC. A good streamer (check out Lumin, Aurender, Innuos) and a separate DAC will be a solid investment if you’re serious about exploiting the true potential of high resolution streaming available through Qobuz.

Both Lumin and Aurender also offers streamer with built in DAC within your budget.

I've found that both the streamer and DAC are of almost equal importance when streaming music. I moved from Node 2i to Sonore opticalRendu streamer in my 2 channel system and the improvement in SQ went above and beyond my expectations. At least in my case, the biggest impact was a noticeable reduction in the noise floor.