With the editing improvements of Confluence, when creating a blank page, it will be a center-aligned page. To change this option, the user must access the profile picture > Settings >Editor and then, tap make page full-width so all brand new blank pages will be using this option.

As this is a change that is applied only for individual profiles, this is a suggestion to have a global configuration to have new blank pages using full-width as well, instead of only center-aligned.