How to display multiple multi-value fields inside one for loop?
If you use square brackets [] in twig, you don't need a period .

{% for key, item in content.body if key|first != '#' %}

  {{ item }}

  {{ content.field_text[key] }}

  {{ content.field_image[key] }}

{% endfor %}




A better solution for this might be a field collection or a paragraph, because you depend on that the user is keeping the deltas of the fields in sync.