I have a medical client and they want to upload and post pdf automatically.
So I stumbled upon frontend uploader, which allows users to upload and post an image to a blog post. It does however post with a pdf, but it goes straight to the media library.
So a alternative solution I came up with is getting the pdf to jpeg, and then just upload the jpeg along with the blog post.
single-cpt.php
template automatically look for a PDF among the post's attachments, then embed/display the first PDF it finds (which may require another plugin).