How to add term programmatically in Paragraph field?
First load the node already created.
Second, create a paragraph like you did but for taxonomy term add "target_id" and for value choose a term id. 
Set the paragraph value to your field of type paragraph from node. Also you need to save the node.

    $node = Node::load($nid);    
     $paragraph = Paragraph::create([
            'type' =&gt; 'gallery_image',
            'field_type_createurs' =&gt; ['target_id' =&gt; $value],
          ]);
          $paragraph-&gt;save();

          $current[] = [
            'target_id' =&gt; $paragraph-&gt;id(),
            'target_revision_id' =&gt;$paragraph-&gt;getRevisionId(),
          ];

   $node-&gt;set('your_field', $current);
   $node-&gt;save();


Varible $value is a term id.

Hope to help you.