Unique id to recurring field in twig - Drupal 8

I have a Drupal content type that uses multiple referenced entities of the same type (say, "related products")

I want to give the title field of every related product a unique ID. It can be the product name, an iterator, the ID of the product's node, whichever is easiest.

I created a twig template that overrides the title of said node in said content type: field--node--title--my-content-type.html.twig but I have no idea where to go from here.

I can add a custom id with

{% set attributes = attributes.setAttribute('id', 'customID') %}

but that's static, and would not be unique when the field is called multiple times.

{% set node = element['#object'] %} and {{ item.content['#node'].field_name.value }} as recommended here don't work for me.

If possible, I want to solve it twig-only, without any additional php code.

any pointers or suggestions are much appreciated

You can modify the code that loops through the items array.

For example, I added an iteration index:

field--node--title--my-content-type.html.twig

{# Here I coppied template from web/core/modules/system/templates/field.html.twig and modified it #}
{%
  set title_classes = [
  label_display == 'visually_hidden' ? 'visually-hidden',
]
%}

{% if label_hidden %}
  {% if multiple %}
    <div{{ attributes }}>
      {% for item in items %}
        <div{{ item.attributes }}>{{ item.content }}</div>
      {% endfor %}
    </div>
  {% else %}
    {% for item in items %}
      <div{{ attributes }}>{{ item.content }}</div>
    {% endfor %}
  {% endif %}
{% else %}
  <div{{ attributes }}>
    <div{{ title_attributes.addClass(title_classes) }}>{{ label }}</div>
    {% if multiple %}
    <div>
      {% endif %}
      {% for index, item in items %}                                     {# use index #}
        <span>{{ index }}</span>                                         {# and print it #}
        <div{{ item.attributes }}>{{ item.content }}</div>
      {% endfor %}
      {% if multiple %}
    </div>
    {% endif %}
  </div>
{% endif %}

Result: