Is there something wrong with the PreSonus 44VSL?
Computer connects to 44VSL via USB cable. Audio output from computer goes to 44VSL.
44VSL connects to monitors and headphones.
You control the volume of your monitors using the Main knob on the 44VSL, same for headphones and Phones knob.
The 96 kHz/24 bit interface should do just fine for everything.
Or am I missing something?