@pram16359 und ich haben zusammen die Lösung ein wenig optimiert.
Ab Shopware 6.5 muss das folgende in die Datei
{{ThemePfad}}/src/Resources/views/storefront/component/line-item/element/delivery-date.html.twig
{% sw_extends '@Storefront/storefront/component/line-item/element/delivery-date.html.twig' %}
{% block component_line_item_delivery_date_inner %}
<div class="line-item-delivery-date">
{% set gap = lineItem.payload.releaseDate|date('U') - "now"|date('U') %}
{% if gap > 0 %}
{% set earliestnew = deliveryPosition.deliveryDate.earliest|date('U') + gap %}
{% set latestnew = deliveryPosition.deliveryDate.latest|date('U') + gap %}
{% else %}
{% set earliestnew = deliveryPosition.deliveryDate.earliest|date('U') %}
{% set latestnew = deliveryPosition.deliveryDate.latest|date('U') %}
{% endif %}
{{ "checkout.lineItemDeliveryDate"|trans({
'%earliest%': earliestnew|format_date('short', locale=app.request.locale),
'%latest%': latestnew|format_date('short', locale=app.request.locale)
})|sw_sanitize }}
</div>
{% endblock %}
Bis Shopware 6.4 muss die Datei
Resources/views/storefront/page/checkout/checkout-item.html verwendet werden.