"Need" Roon, Bluesound Node, or or other streamer?

I am also in the camp that MQA isn’t worth stressing over.  If you buy the Node then you do have to use its DAC for MQA.  The DAC in the Node isn’t unlistenable, but it’s a rare person in  these forums that prefers it to their external DACs.  Fwiw, the Node DAC has recently been upgraded, and I haven’t heard it, though I have only seen 1 user in Agon say it was a significant upgrade.
   Roon is a software application that organizes all of your music files, both on hard drives and streaming services, and also attempts to improve Sound Quality.  The previous sentence is as pithy as I can get describing it.  In some respects it resembles Audirvana Plus, which you seem to have had an unhappy experience with.  I suggest that you Google or You Tube Roon as there is a lot more to it, and Roon users here may have much more to add.  Roon is a large and complicated program that doesn’t always run well on computers and streamers, so Roon started manufacturing hardware, essentially dedicated streamers customized to run their software 

You are really asking about three separate things:
User Experience Software (Roon vs. BluOS)
Playback Hardware (which requires 3 parts: streamer/renderer, library storage
Control Hardware(tablet and/or phone)

I'd suggest watching some youtube videos of users demonstrating use of Roon(e.g. Hans Beekhayzen) and BlueOS and decide what experience you'll be happy with. For me, Roon was a game changer and I can't imagine going back to any other app. It makes choosing what to play more fun and increases engagement. This also applies with family and visitors. 

If you head this direction, building a NUC or buying Small Green Computer products both will work great. Internal storage vs. NAS(e.g. Synology or QNAP) for you library really depends on size of your present & future library.  

Any of the above and the Blue Node will all sound better than most Mac/PC setups unless you go to great length and cost to overcome those platforms disadvantages(e.g. NOISE, frequent OS updates screwing things up, many others)

Yes, your DAC is probably way better than that in the Blue Node and I agree that MQA is a sham. I would suggest not making MQA part of your rationale for choosing your path forward. Use your external DAC and a tablet/phone/mac as remote for any of the above. Cheers,
Spencer

We are streaming experts We sell bluesound, lumin,roon and 532evo servers

The node is best viewed as  a starter streamer

The roon nucleus is good

The lumin u1 mini is your best bet for a really top performer for the price

And te 432evo servers sound the best

Dave and troy
AUDIO INELLECT NJ
BLUESOUND,LUMIN, roon and 532evo dealers

+1 on dropping the MQA requirement.  Do some critical comparison MQA vs standard 24/96.  Opens up your options as well

Another vote on dropping Tidal. My experience is that it sounds worse than Spotify Premium.

Another streamer to consider is the Pro-ject Stream Box S2 Ultra which is supposed to sound better than the Bluesound Node. It’s about $750-800 new and you can easily get one used for about $500. It runs on the open source Volumio software so there is ongoing work on improving the interface. Some other interface software is slicker, but Volumio works fine for me. The Pro-ject doesn't have a lot of flashy features such as LCD screens, built-in DAC or internal memory for storage, but its materials cost seems focused on areas that improve sound quality such as the isolation of its power supply and cleaning up its USB output.

Here's some comments from the designer about the considerations behind the design of the Pro-ject: https://www.avforums.com/threads/why-is-pro-ject-stream-box-ultra-s2-so-expensive-700euro-for-an-r-pi.2175090/

What I heard about the current version of Roon is that it doesn’t sound as good as prior versions or compared to other streamer software.