I copy a link address from a PDF file located in the page's attachments (or from the attachments of another page).
Pasting the link in a page results in a plain URL link, and that's it. There are no options available to change the appearance of the link.

Inserting, e.g., a link from youtube, the options are available:

Does this mean smart links do not work with files stored within Confluence?
The point is, I like to see the link as a card or even embedded (with thumb preview)
The only possibility to get a card or an embedded icon is to download the attachment and then added with a drag-and-drop to the page.
I truly hope there is a more brilliant workaround for this issue.
I highly appreciate all the suggestions.
Michael