What controls the placement of links relative to the body?

I am struggling with getting the "Read more" and "Add new comment" links placed below the body on a custom node content type called "Wikitext" that has been created using the GUI on a Drupal 8.9.17 website.

The site is running the default theme (Bartik) and I have not edited any templates. The built-in content type "Article" shows these links below the body. "Wikitext" is supposed to be identical to "Article", but displays them above the body.

I've unticked "Show reply form on the same page as comments" on the comment settings form for both content types.

Below the acreenshot is a copy of the "Manage display" form. It is identical for both content types, and has "Links" and "Comments" as the last two fields to display.

I have looked very carefully, but cannot locate anywhere in the GUI where I can control the placements of these links. Does anybody know where to look?