Lovelace: Mini Media Player

This was a reply to @staceydodds

I do not believe you can stream urls to alexa devices
:frowning_with_open_mouth:

Can you create a shortcut to directly open the Sonos radio station-favorites? Instead of having to tap on the media-icon, then “Search Media” → “Favorites” → “Radio”.

try as follows:

type: custom:mini-media-player
entity: media_player.gunters_echo_dot
shortcuts:
  buttons:
    - name: Radio21
      type: custom
      id: play radio21
      icon: mdi:radio

@Reini79
I’m sorry that I’m only writing now
Thanks for your answer!
This code works now:

type: custom:mini-media-player
entity: media_player.gunters_echo_dot
artwork: cover
info: short
shortcuts:
  buttons:
    - name: Radio21
      icon: mdi:radio
      type: music
      id: media-source://radio_browser/e417eec8-b2ad-466f-9a3c-ce4abd05c37a
volume_stateless: true
announce: true
group: false
toggle_power: false
source: full
sound_mode: full

Unfortunately the volume changes independently.
Advertising louder
Music quieter
News quieter.
Can that be changed?