If it can help ;)

thanks to Youtube : OverSeas Media

{# languagesForm.html.twig #}

{% from 'macros.html.twig' import languageFormMacro %}

<div class="languages-container form-control">
    <h3>{{ form_label(languagesForm) }}</h3>
    <button type="button" class="add-item-link btn btn-success" data-collection-holder-class="languages">
        <i class="fa-solid fa-plus"></i>
    </button>

    <ul class="languages collection"
        data-index="{{ languagesForm|length > 0 ? languagesForm|last.vars.name + 1 : 0 }}"
        data-prototype="{{ languageFormMacro(languagesForm.vars.prototype)|e('html_attr') }}"
    >
        {% for languageForm in languagesForm %}
            <li>
                <div class="form-control">
                    {{ languageFormMacro(languageForm) }}
                </div>
            </li>
        {% endfor %}
    </ul>
</div>

{# macros.html.twig #}

{% macro languageFormMacro(languageForm) %}
    <div class="row">
        {{ form_row(languageForm.name) }}
        {{ form_row(languageForm.expertise) }}
    </div>
{% endmacro %}