Digital Advice

Here’s a Schiit Bifrost DAC for $300. 
And the Audiolab 6000CDT CD Transport for $335

Use your Mac to stream to Schiit via USB. This will beat WiiM and Bluesound. 

New Vaults are over his budget. Personally I would stay away from a used Vaults. I don’t know what refurbished means, except they scrubbed the hard drive. My Vault started failing after about 3 years, right when the warranty was up. I think he is safer going with a Wiim and a transport, but adding a program like Audirvana greatly improves using a PC as a streamer, because it turns off some other parts of the PC that contribute to the noise. It probably costs the same as a Wiim

Moving away from computer streaming (MacBook/Audirvana) to a dedicated streamer (Aurender) produced significant improvement in all areas of SQ but most notably, the removal of fatiguing “digital glare”.  I recommend you make the move to a server/streamer.  Join a streaming service like Qobuz and they will have almost all the albums in your CD collection at your fingertips with SQ better than CD.  Burn any album in your collection not on Qobuz and your collection is complete and conveniently available.  If you can up your budget to $850-900 you can get a preowned Aurender N100H offering much better SQ than any Bluesound Node/Valt model.  If not, IFI has models in your budget liked by the press as an alternative to Bluesound.  

I would recommend Node - my rationale is it’s a streamer/DAC. You could connect your Mac to it and I found streaming to be a lot more convenient that sifting through my computer for files. 
 

I also prefer streaming DAC for simplicity. 

Check out the BlueSound Node N130 or newer. It streams Amazon and does great things for little money. New or used.

All the best.