Using Spotcast with current media player source

Configuration Frontend
1

In setting up a card for Spotify using the Mini Media Player custom card, I have 2 options to create shortcut buttons:

image
image786×460 97 KB

This variant allows me to play a playlist on whatever device I’m currently listening on:

icon: mdi:beach
name: pool
type: playlist
id: spotify:user:spotifyUser:playlist:4JhuWvKcHLzwtZ

This variant uses Spotcast, and has the extra features I want (shuffling the playlist and setting the starting volume), but requires I specify a device (and will not accept the Spotify device (media_player.spotify_spotifyUser) that I use in other areas:

icon: mdi:beach
name: pool
type: service
id: spotcast.start
data:
  device_name: Library speaker
  uri: spotify:playlist:4JhuWvKcHLzwtZ
  random_song: true
  shuffle: true
  start_volume: 20

Is there a way I can achieve both? I would like the features in the Spotcast variant, but without specifying a source device in the first version.

Thank you!