Neo: children won't display or I get all() deprecation notice
For anyone else having a similar problem, the solution was this:

    {% for module in entry.pageBuilder.all() %}
        {% do module.useMemoized(entry.pageBuilder) %}
    {% endfor %}

    {% for module in entry.pageBuilder.all() if module.level == 1 %}
        {% if module.type != 'moduleColumn' %}
            {% include '_partials/page-builder/_' ~ module.type %}
        {% endif %}
    {% endfor %}


and then inside _moduleRow.twig

    &lt;div class="row flex flex-wrap"&gt;
        {% for module in module.children.all() %}
            {% if module.type == 'moduleColumn' %}
                &lt;div class="md:w-1/{{module.width}} "&gt;
                {% for module in module.children.all() %}
                    {% include '_partials/page-builder/_' ~ module.type %}
                {% endfor %}
                &lt;/div&gt;
            {% else %}
                {% include '_partials/page-builder/_' ~ module.type %}
            {% endif %}
        {% endfor %}
    &lt;/div&gt;