This isn't a bug. The block listview he's referring to is a way to give an overview of the block hierarchy, and it not meant to be a complete representation of the entire post/page. If he enters forms mode, and reviews his post while in forms mode, he can edit his paragraphs to make them headings. We've compiled a nearly complete list of shortcut keys he can use to more efficiently use the block editor with a screen reader: https://www.customerservant.com/an-in-depth-introduction-to-the-wordpress-block-editor-for-screen-reader-users/