No DispalyPort Option in the Audio Output Device Menu, Nvidia Drivers

I can not display my monitor connected to DisplayPort (AW2518HF, connected external speakers) in this drop-down menu:
Settings> Sound> Output> Output Device.

I have opened the Nvidia X server settings and I can assure you that DP Audio is enabled. In addition, I started Windows 7 and was able to select it and play a perfect sound.

I'm using a GTX 750 (EVGA; they've added a DP port in their version) with the 418 driver installed from Software & Updates on Ubuntu 19.04.

here is aplay -l

**** List of PLAYBACK Hardware Devices ****
card 0: PCH (HDA Intel PCH), device 0: ALC887-VD Analog (ALC887-VD Analog)
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia (HDA NVidia), device 3: HDMI 0 (HDMI 0)
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia (HDA NVidia), device 7: HDMI 1 (HDMI 1)
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: NVidia (HDA NVidia), device 8: HDMI 2 (HDMI 2)
  Subdevices: 1/1
  Subdevice #0: subdevice #0