Yes, but separately: “Netflix Spatial Audio” (available on Premium plan) works with any stereo headphones, simulating 5.1 or Atmos. It is not true multichannel but can be effective.
Yes, but only when system audio is set to “Dolby Atmos” (requires HDMI to Atmos AVR). netflix surround
Mobile devices default to stereo to save bandwidth. Casting to a TV may reactivate surround. netflix surround