Get this - HOLO AUDIO RED Audio Network Player
and use either Moode Audio or RoPieeeXL (which are popular audiophile-focused Linux distributions you can install on the Red's microSD card), you can typically connect a USB hard drive or flash drive to one of the USB-A ports on the back of the Red.
The software on the Red will then be able to mount and access the music files on that external drive, allowing you to browse and play them through the Red, sending the digital signal to your DAC @paulie123