You can get a PC laptop for around $600 with 1Tbyte drive in it from Costco.
You can rip of your files to FLAC or wav to this disk, using dbpoweramp.
You can run the Connect to a Synchro-Mesh reclocker to reduce the jitter to 7psec. Here are the before and after jitter plots:
https://www.audiocircle.com/index.php?topic=154310.0
The Synchro-Mesh connects to your DAC with a second cable.
I highly recommend using good BNC cables like Empirical Audio Standard BNC for $275.
You will have a world-class digital source for around $1900 for Sonos Connect, Synchro-Mesh, BNC cable and Laptop.
This will outperform ANY transport or server you can buy. It will also give you another personal computer to use for other things.
Steve N.
Empirical Audio