sonos_mute_toggle.yaml

alias: Sonos Mute Toggle
sequence:
  - choose:
      - conditions:
          - condition: template
            value_template: >-
              {{is_state_attr('media_player.sonos', 'is_volume_muted',
              false)}}
        sequence:
          - service: media_player.volume_mute
            target:
              entity_id: media_player.sonos
            data:
              is_volume_muted: true
    default:
      - service: media_player.volume_mute
        target:
          entity_id: media_player.sonos
        data:
          is_volume_muted: false
mode: single