Turns out we don't need to override the field at all; our surrounding HTML comes from the paragraph

agaric/templates/field/field--paragraph--text--field-text--preview.html.twig

@@ -1,19 +0,0 @@
-{% extends "field.html.twig" %}
-{#
-/**
- * @file
- * Default theme implementation for a text field.
- *
- * A 'content' class is added to provide default styling of base elements such
- * as paragraphs and lists that may not have classes assigned to them. This
- * allows user entered content to have default styling without interfering with
- * the styles of other UI components such as system generated lists or other
- * dynamic content.
- *
- * @see https://www.drupal.org/node/2539860
- * @see http://bulma.io/documentation/elements/content
- *
- * @ingroup themeable
- */
-#}
-{% set attributes = attributes.addClass('content') %}