NAS Storage and Streaming for Hi Def audio, What NAS Hard drive system best for Mac..

I have a WD MY Cloud EX 2 bay that has been working well for the past 6+ years. I do not have experience with any other NAS so can't compare.

The one thing that I don't like is that it utilizes a proprietary file format. This isn't an issue with daily use but is going to make the current upgrade (drive size) process more difficult. I will first need to copy everything over to another drive, replace the NAS drives and copy back. Audio files are already backed up elsewhere, but will need to do the same for movies.

I would suggest setting up for RAID 1 (redundancy) and not go excessive on storage space. 2TB has been serving me well for six years, currently have ~1TB audio (mostly 16/44.1 FLAC with some HD) and close to 1TB of movies (these don't really need to reside there all the time but it's convenient). I will probably just upgrade to 4TB, may consider 8TB depending on drive deals. Drives have a lifespan (I am likely pushing it at six years), so paying for unused storage could end up being a waste.

As far as MAC goes I can't help you out, I am a Windows PC guy but am sure plenty utilize the WD My Cloud without issues. And for software, I wrote my own PC & iOS (iPhone) app for playback & remote control.

The advantage of QNAP lies in the higher-level models with i5 and i7 processors.  With those you can run everything on the NAS with no need for an external PC or Mac.  I'm running Roon core and Roon DSP engine on an i5 TVS-882 with six disk bays and two SSD bays to host Roon and cache the disk drives.

I appreciate all this good info. I looked into the Melco devices and they have some really good reviews and great info on high end streaming and stoarage.   But it almost feels like it’s more of a high end music server with the addition of small NAS storage . But I appreciate how they developed there HI Def storage/NAS of building the storage with more like smaller flash drives to developed for the one Storage for speed and hi end quality, ( that is not a exact technical description, but a quick overal review on my end).  How Melco is creating a dedicated high end audio music streaming and storage, vs using and going the universal market of Hard disk storage.
I did like the QNAP line for what it has to offer, but wasn’t aware of the line that you recommended. I appreciate the WD line for speed and cost savings, but wasn’t aware of the process for additional storage. Looking into the Melco has brought forward an important issue of the noise added when using universal NAS data storage vs a dedicated Melco audio line that has developed for hi end audio. Now it’s a matter of cost and dollars, what I can afford, or more important is starting off in the right direction, no mattered of  the higher cost of the dedicated audio music streamers and storage, but unfortunately their a Finacial restraints that I also have to consider. I’m still open to suggestions on the best NAS storage system to start and build from with music streaming still a large part of the complete NAS system.
While reading reviews on the Melco N1A/2 , it lead me to a the 
Innous line of music Servers which also stood out. The one I was looking into was the : Innous Zen MK3 1 TB music server for apx.
$1,850.00 which Had some nice reviews for it delievery of hi end music. But this also has got me a little more confused on the direction of my digitial storage and streaming, though it’s getting very interesting.

IME the best approach is computer-grade i5 or i7 NAS in conjunction with high-performance Ethernet-to-USB renderers like Micro- or UltraRendu or SOtM.  Separate the EN-to-USB conversion with audiophile pieces from the computer and storage.  It's scalable and relatively cheap.

After reading  more on the Melco N1A/2 music storage and streamer, which so far has received great reveiws , talks about the pick up of noise with the conventional Hard drives and cables, would what you suggest be doing that with all the various drives and cables. Honestly, you kind of lost me with some of the technical specs that you described. I’m just now researching the terms you described, But what Melco was describing inregards to the difference’s of a dedicated audio Music storage and streamer makes some sense inregards to build up of noise. 
Again , I’m very new to this technology and I’ve been reading for the last couples of weeks , and I feel I’m just at the tip of the iceberg when it comes to all this technology with high end audio storage and streaming.

I’m basically an analog guy but several years back wanted to get into digital. Went thru a LOT of DAC’s but did use a G-Technology 4TB RAID 2 NAS so it’s always backing the data up. Have never had an issue and even though I still enjoy analog running out of the NAS to a MAC (using Pure Music) it sounds wonderful.