the pages shows support for 5.1 surround but the game only runs 2.0 for me and I found some posts via google that seem to indicate that for other users as well
Topic on Talk:The Outer Worlds
Firstly, the game doesn't use the subwoofer, so it's only 5.0 surround. As for there being "no 5.1 surround sound", I noticed it mainly occurring during combat, with enemies and allies all around you. The signal beyond the front speakers is not as strong, but it's there - especially if you use something like Special K to monitor the sound output.