Big source improvement using CD player

I recommend a Sony SCD 595 sacd/cd changer.Reviewed very highly.Reviewers thought it was better than the 777. I bought mine new for 199.00.Mine is still going strong over ten years.This is a multi channel unit that outputs DSD into my Marantz receiver’s analog inputs with all decoding being done by the Sony.The Marantz lets you play the sacd with no decoding from the receiver.I have played DSOM many times in 5.1 surround which is a real trip.

Wait a minute, you have a very capable DAC in that NAD so why don't you just rip cd's and play them off a network drive? You can also download hi-res files and play them at better than cd quality. I don't like your NAD's player interface, as I prefer my setup below:

HP laptop, Win7
JRiver Media Center
USB out
Mytek DAC

So, I would use your NAD as a DAC only, from my setup's USB output.

JRiver also has room correction but so does your NAD, to some degree. That goes a long way to better sound if you take the time to learn to do it right. You have so much flexibility with JRiver and sound quality is superb.

You said above you want the convenience of many songs on a DVD. Forget it and just play ripped files. FYI, my laptop and JRiver above cost $100 - can't beat that!

The 105 has a Tidal selection on its menu. You have to download the Oppo Media app onto your phone to operate 

In your price range I can recommend CAMBRIDGE AUDIO - CXU ($800) Decent player with five separate Wolfson WM8740 DACs on board and upsampling (Adaptive Time Filtering). upsamples all audio up to 24-bit/192kHz. “Pure Audio” mode could be used to disable all processes except those participating in audio reproduction - cool future, definitely benefits SQ. Wide range of Disc types: CD, SACD, Blu-ray (BD) including BD-3D, DVD, DVD-A, AVCHD, HDCD, Kodak Picture CD, CD-R/RW, DVD+-R/RW, DVD+-R DL, BD-R/RE. Good luck!

https://www.musicdirect.com/disc-player/cambridge-audio-cxu-universal-blu-ray-player

I have the NAD C658 and Cambridge Audio CXC using COAX.
Sound great through an original Peachtree Audio Nova (amp only) to SVS Ultra Towers and a small Outlaw Audio sub.  

I also use a ripper for my Mac but you could combine all this PLUS add music to another room with a Blusound Vault 2i (one of my next steps....). It would rip and store your CDs in WAV or AIFF (my preference) or any other format for playback on the C658 or whatever you have the Vault connected to (receiver, amp, powered speakers) or both simultaneously. 

Good luck!!