CKEditor 5 has a plugin called Special Characters that Drupal’s CKEditor 5 module makes available to use. The plugin provides a toolbar button that can be used to insert characters that may not be easy to type manually using a keyboard, especially for people who are not used to using them frequently.
It comes with a list of default special characters, organized by category. One such category is for Latin characters and includes characters such as Ā, Ć, and Ē.