Well you should be able to pull posts and make newsletters out of them.
E.g., if you have self-hosted both Mautic and WP instances, I don’t see any limitations why you could not pull WordPress posts from its DB like this:
[code]SELECT wp_posts.id as post_id,
(SELECT name FROM wp_terms WHERE term_id = (SELECT term_id FROM wp_term_taxonomy WHERE term_taxonomy_id=tti.term_taxonomy_id)) as post_category,
(SELECT slug FROM wp_terms WHERE term_id = (SELECT parent FROM wp_term_taxonomy WHERE term_taxonomy_id=tti.term_taxonomy_id)) as post_parent,
(SELECT display_name FROM wp_users WHERE ID=wp_posts.post_author) as post_author
SELECT object_id, wp_term_relationships.term_taxonomy_id FROM wp_term_relationships
(SELECT wp_term_taxonomy.term_taxonomy_id FROM wp_term_taxonomy WHERE parent=INSERT_PARENT_ID_HERE OR parent=INSERT_ANOTHER_PARENT_ID_HERE) AS term_taxonomy
ON wp_term_relationships.term_taxonomy_id = term_taxonomy.term_taxonomy_id
) AS news_posts
LEFT OUTER JOIN
SELECT term_taxonomy_id, object_id
) AS tti
ON tti.object_id = wp_posts.id
WHERE wp_posts.post_status = 'publish'
ORDER BY wp_posts.post_date DESC[/code]
and, then, process them and convert them into emails by pushing their HTML code into Mautic using its REST API.
So technically speaking, yes, you are able to do it.