Testing field value in twig template
Use node (if this is a node template) to get the field value, see Conditional statement doesn&#39;t work in node.html.twig. Another reason in this case is that Yes/No would be translatable in a multilingual site, while the field value from nodeis the untranslatable left key of a select list.

If it is not a node template look at the variables listed at the top of the template, for example paragraph.html.twig:

/**
 * @file
 * Default theme implementation to display a paragraph.
 *
 * Available variables:
 * - paragraph: Full paragraph entity.

 * - content: All paragraph items. Use {{ content }} to print them all,
 *   or print a subset such as {{ content.field_example }}. Use
 *   {{ content|without('field_example') }} to temporarily suppress the printing
 *   of a given child element.


Here the variable for the entity is paragraph and for the render array content.

So use {{ content.field_example }} to print fields and {{ paragraph.field_example.value }} to get field values from the database.