Get a link field url and value in Twig for both internal and external links

Drupal's link field is quite generic. You can both add internal paths as external links. Here is how get the correct values in twig.

Solution

{% if content.field_cta %}
  <a href="{{ content.field_cta.0['#url'].toString() }}" class="btn-secondary">{{ node.field_cta.title }}</a>
{% endif %}
// If you are doing this inside a paragraph, use paragraph instead of node