When you click a Tag you are directed to Tags results that are rendered by ../components/com_tags/tag/default_items.php. By overriding this file you can have your specific look. A serious issue with the above file is the rendering of the truncated text that has HTML tags and this can result in a breaking layout. For example, if you have an opening Unordered List tag without the closing tag, a usual issue, that breaks the whole layout.
The code (in Joomla 4) that displays the truncated text from the main article text is:
<?php echo HTMLHelper::_('string.truncate', $item->core_body, $this->params->get('tag_list_item_maximum_characters')); ?>
So, the question is: How can we modify the above code to strip HTML tags?