Add special character to ckeditor5 in Drupal 9 - drupal

Question

The CKEditor 5 documentation shows the easy way how to add special characters to CKEditor 5 (https://ckeditor.com/docs/ckeditor5/latest/features/special-characters.html):
import SpecialCharacters from '#ckeditor/ckeditor5-special-characters/src/specialcharacters';
import SpecialCharactersEssentials from '#ckeditor/ckeditor5-special-characters/src/specialcharactersessentials';
function SpecialCharactersEmoji( editor ) {
editor.plugins.get( 'SpecialCharacters' ).addItems( 'Emoji', [
{ title: 'smiley face', character: '😊' },
{ title: 'rocket', character: '🚀' },
{ title: 'wind blowing face', character: '🌬️' },
{ title: 'floppy disk', character: '💾' },
{ title: 'heart', character: '❤️' }
] );
}
ClassicEditor
.create( document.querySelector( '#editor' ), {
plugins: [
SpecialCharacters, SpecialCharactersEssentials, SpecialCharactersEmoji,
// Other plugins...
],
toolbar: [ 'specialCharacters', ... ],
} )
.then( ... )
.catch( ... );
But I have not found how to change it in Drupal 9. Does any special hook exist for it?
I have tried to create a new module based on starter template (https://git.drupalcode.org/project/ckeditor5_dev/-/tree/1.0.x/ckeditor5_plugin_starter_template):
chars.info.yml
name: Characters
type: module
description: "Provides CKEditor plugin."
package: CKEditor 5
core_version_requirement: ^9.2 | ^10.0
dependencies:
- drupal:ckeditor5
chars.ckeditor5.yml
chars_chars:
ckeditor5:
plugins:
- chars.Chars
drupal:
label: Characters
library: chars/chars
elements: false
chars.libraries.yml
chars:
js:
js/build/chars.js: { preprocess: false, minified: true }
dependencies:
- core/ckeditor5
ckeditor5_plugins/chars/src/chars.js
import { Plugin } from 'ckeditor5/src/core';
import SpecialCharacters from '#ckeditor/ckeditor5-special-characters/src/specialcharacters';
export default class Chars extends Plugin {
init() {
const editor = this.editor;
editor.plugins.get( 'SpecialCharacters' ).addItems( 'Emoji', [
{ title: 'smiley face', character: '😊' },
{ title: 'rocket', character: '🚀' },
{ title: 'wind blowing face', character: '🌬️' },
{ title: 'floppy disk', character: '💾' },
{ title: 'heart', character: '❤️' }
] );
}
static get pluginName() {
return 'Chars';
}
static get requires() {
return [SpecialCharacters];
}
}
This code was built by yarn run build and insert to js/build/folder. When CKEditor is loaded the console throws: CKEditorError: plugincollection-plugin-not-found {"plugin":null}