In ckeditor 5, can a css file be listed in the theme .info, that will style the editor to better resemble your site theme, rather than the admin theme.
I believe we used to do this using the WYSIWYG module, but here's a newer reference from Drupal: https://www.drupal.org/docs/core-modules-and-themes/core-modules/ckedito...
Hi, there is a change record with a section called "Changes for Themes that Provide CKEditor-specific CSS", see https://docs.backdropcms.org/change-records/ckeditor5-upgrade. Hope this helps!