Universal Media Player - help with commands

I’m trying to build a universal media player for the AmpliPi. For whatever reason, I cannot get any of the media controls (play/pause/next/prev) to appear. I have verified that my rest_command is functioning through the developer tools section. Any pointers appreciated.

media_player.yaml:

- platform: universal
  name: AmpliPi Zone 1
  commands:
    volume_up:
      service: rest_command.amplipi_zone_vol
      data: 
        zoneId: 1
        volume: "{{ states('sensor.amplipi_zone_1_volume') | default(0.00) | float + 0.01 }}"
    volume_down:
      service: rest_command.amplipi_zone_vol
      data: 
        zoneId: 1
        volume: "{{ states('sensor.amplipi_zone_1_volume') | default(0.00) | float -  0.01 }}"
    volume_set:
      service: rest_command.amplipi_zone_vol
      data: 
        zoneId: 1
        volume: "{{ volume_level }}"
    volume_mute:
      service: rest_command.amplipi_zone_mute
      data: 
        zoneId: 1
        mute: "{{ is_volume_muted }}"
    select_source:
      service: rest_command.amplipi_zone_source
      data: 
        zoneId: 1
        sourceId: "{{ source }}"
    # media_play:
    #   service: rest_command.amplipi_stream_exec
    #   data:
    #     sid: "{{ source }}"
    #     cmd: "next" 
    # media_pause:
    #   service: rest_command.amplipi_stream_exec
    #   data:
    #     sid: "{{ source }}"
    #     cmd: "next" 
    # media_previous_track:
    #   service: rest_command.amplipi_stream_exec
    #   data:
    #     sid: "{{ source }}"
    #     cmd: "next"     
    media_next_track:
      service: rest_command.amplipi_stream_exec
      data: {sid: 1002, cmd: next}
  attributes:
    volume_level: sensor.amplipi_zone_1_volume
    is_volume_muted: sensor.amplipi_zone_1|mute
    state: sensor.amplipi_zone_1
    source: sensor.amplipi_zone_1_source
    source_list: input_select.amplipi_inputs|options
  device_class: speaker

rest_command.yaml:

amplipi_stream_exec:
    url: http://X.X.X.X/api/streams/{{ sid }}/{{ cmd }}
    method: POST
    headers:
      accept: "application/json"