How to prevent HA script starting next action while alexa_tts still speaking?

Third party integrations
1

Is there some way how I could prevent script starting next in sequence while Alexa is still speaking without setting explicit delay for x seconds since length of text may vary?

In script below Alexa is still speaking whatever is passed in as “message” but volume is already changing in the middle of sentence.

alexa_speak:
  sequence:
    - service: input_number.set_value
      data_template:
        entity_id: input_number.alexa_volume_holder
        value: "{{ states.media_player.mana_alexa.attributes.volume_level | default(0.4) }}"
    - service: media_player.volume_set
      data_template:
        entity_id: media_player.mana_alexa
        volume_level: "{{ volume | float }}"
    - service: media_player.alexa_tts
      data_template:
        entity_id: media_player.mana_alexa
        message: "{{ message }}"
    - service: media_player.volume_set
      data_template:
        entity_id: media_player.mana_alexa
        volume_level: "{{ states.input_number.alexa_volume_holder.state | float }}"
2

there is no way to determine that alexa is ready with speaking a text.
alexa doesnt give a feedback when she has spoken the text.

so setting a delay is the only option.