Introduction text before posts on blog page

Hello everyone,

I am currently facing a problem which I never thought would exist because it is so absurd.

On a blog page, I want to add a custom headline in the editor, as well as introductory text and possibly a banner image, before the actual posts are listed.

However, this does not want to succeed. The content I have created in the editor on the blog page simply does not appear in the frontend. There are only the posts to see.

How can this be done?

The page I need help with: [log in to see the link]