Hey @mark-15 anything is possible, though we don't officially support anything other than slate. We have a community member that built a plugin for Lexical, but nothing for ckeditor at this time.
To expand on this, using ckeditor would actually be quite easy. Because it stores its contents as a string, you would just need to make a custom Field component for any given text field.
Then, within that custom field component, you would render ckeditor accordingly. Would be easy!