DAC connection to computer

@8th-note You can use a phone or tablet to control foobar2000 in your existing setup. This thread has a few suggestions.

USB. No one yet explained any physical concepts of "bad sounding" PC. You can use reclock/DDC if you are really concerned with "noise" coming from the PC.

Use HDMI.  It delivers bit-perfect digital audio to the DAC.  Only from the DAC to the speakers is quality an issue.  The data that goes into the HDMI is identical to the data that comes out of it, unless something is very wrong with the cable.