The list of latest posts is not a page, but is dynamically generated, so there’s no page to edit. If you make a child theme and change the home.php template file, you will see your changes. If you switch the Setting > Reading for the home page to be a Page instead of Latest Posts, then you can use any of your Pages. (the Page chosen gives up its URL to be the home page) But if you do this, don’t expect to show all the posts there. There is a problem with pagination, which is different for single Pages and lists of multiple posts.
