Best solution to send digital files to my DAC

I use a CD player, digital out to DAC.  I also stream wirelessly from any Apple device to an Apple TV or an Airport Express.  I also have a Chromecast Audio that works well.
This works for me because I can't really hear any difference between 16/44.1 and any higher resolution.  Jitter may be a problem for some, depending on your DAC (you can always try out a re-clocker).
I know my opinion is controversial.  I have taken super hi-res files downloaded from HD Tracks and listened to them direct with headphones, and then listened to the same source through the AEX (which downsamples to 16/44.1) and my accuracy at identifying the source (blind testing) is 50%.  If there is a difference, I cannot discern it with any of my equipment.

Another thing to consider is streaming services.  I use both Tidal hifi and Idagio.  Most anything I want to listen to is available from those services, so the need to go out and buy music, either physical or downloaded, is greatly diminished.  I will buy an occasional obscure recording, and I will buy records (another story for another time), but I have significantly downsized my collection of CDs.  I have about 75 CDs ripped to a hard drive (mostly alac, some Flac, about 50GB), but stopped when I realized most of that material was available on Tidal.  My 500 or so CDs do not take up much room, and I enjoy reading the liner notes!
Again, my approach works because I am completely satisfied with Redbook quality.  If you are pursuing higher resolutions, your life will become considerably more complicated and expensive.  I am blessed that I cannot tell the difference!

Check out Bluesound Node 2i or Vault 2i if you need to rip cds to its internal drive.  

You want a network streamer. Tons of these nowadays at different price points. The best one might be something like the Innuos Zen MK3