This is not so much as an edorsement or recommendation, but you might check out the DAPs by Shanling or Hidiz if you have coin to spare. They use Linux & don’t publish kernel mods, but they do have inexpensive, very small, lightweight options that may fit your needs. I have one & it has a place to have a dedicate device to not chew thru my phone’s battery as well as function as a high-quality USB DAC in scenarios where you don’t have a jack (like my old laptop) or the DAC is horrible (like in my dock for my laptop).