Add ajax on hook_field_widget_paragraphs_form_alter
You should be able to get this information from the submitted data in $form_state, specifically the triggering element.
For example:
use Drupal\Component\Utility\NestedArray;

function _type_paragraph_callback(array $form, FormStateInterface $form_state) {
  $button = $form_state-&gt;getTriggeringElement();
  // Go one level up in the form, to the widgets container.
  $element = NestedArray::getValue($form, array_slice($button['#array_parents'], 0, -2));

  return $element;
} 

I've copied this from the Paragraphs module:
modules/contrib/paragraphs/src/Plugin/Field/FieldWidget/InlineParagraphsWidget.php