Pi 3B Onboard WiFi not found

  1. You don’t want tethering.
  2. Your /etc/connman.conf is showing a preference for ethernet over wifi. You need to reverse that preference.
  3. The output from connmanctl services isn’t right. It seems that you’re running it from a userid that is not osmc. Run it from user osmc and the errors should disappear.
  4. You can configure it through connman (once you sort out point 3 above) and you can preconfigure it for first-boot only using preseed.conf.