I'll repeat no usb out of motherboards is optimal, usb renderers such as Innuos Phoenix or Uptone usbRegen will help, but doing thunderbolt to ethernet conversion and adding FMC (otherwise known as optical conversion) and separate streamer (something like SOTM SMS200 or Sonore OpticalRendu) will be far superior to usb out, even with an added usb renderer. One can do the two FMC for less than $100, add the SOTM at $450 or used for less and have far superior sound than any usb port on mini.
Following link supplies directions and evaluations of this mod for minis, https://audiophilestyle.com/forums/topic/30376-a-novel-way-to-massively-improve-the-sq-of-computer-audio-streaming/