Question

When i publish my web page to the web - all uploaded and embedded files are visible, but inactive - people can't open or download them

Answer 1

Because they do not have the permissions you have "as owner" of the Notion page to click options and get the download link.

It works as any website where you can see videos, but you don't have buttons to download them. The same as they can't change the cover or the page icon, that options are only for you as the page owner.