{% set background %}
  {% set image %}
    // ..
  {% endset %}
  {% include '@bolt-components-background/background.twig' with {
    opacity: 'heavy',
    fill: 'gradient',
    items: [
      image
    ]
  } only %}
{% endset %}

{% include '@bolt-components-broadcast/broadcast.twig' with {
  background: background,
  // ..
} only %}