Upgrade everything if possible , a good usb or Ethernet cable are at least $750 each , ether regen helps most critical Ethernet cable is where the hub is
buy the best dac you can afford ,by far the most important component
for all detail and resolution, sound signature start here . For your budget I would Highly recommend the Denafrips Pontus2 , ifyou could come up with $4500 the
the New Denafrips Terminator2 12 th anniversary but for $2k the pontus 2 beats
many dacs at 2x the cost.