Elementor access settings inside _register_controls function - wordpress

Question

I am using Elementor. In one section user can create categories with repeater field. In other section I would like to list these categories in Select2 control. How could I access category_data in _register_controls function? I know I can access it in render function.
protected function _register_controls() {
$this->start_controls_section(
'content_section',
[
'label' => __( 'Content', 'plugin-name' ),
'tab' => \Elementor\Controls_Manager::TAB_CONTENT,
]
);
$repeater->add_control(
'category_title', [
'label' => esc_html__( 'Title', 'plugin-name'),
'type' => \Elementor\Controls_Manager::TEXT,
'label_block' => false,
]
);
$repeater->add_control(
'category_slug', [
'label' => esc_html__( 'Slug', 'plugin-name'),
'type' => \Elementor\Controls_Manager::TEXT,
'label_block' => false,
]
);
$this->add_control(
'category_data',
[
'label' => esc_html__( 'Category', 'plugin-name'),
'type' => \Elementor\Controls_Manager::REPEATER,
'fields' => $repeater->get_controls(),
'prevent_empty' => false,
'title_field' => '{{{ category_title }}}',
]
);
$this->end_controls_section();
$this->start_controls_section(
'category_section',
[
'label' => __( 'Category', 'plugin-name' ),
'tab' => \Elementor\Controls_Manager::TAB_CONTENT,
]
);
//how could I access category_data here?
$settings = $this->get_settings_for_display();
$category_data = $settings['category_data'];
$cd_arr = [];
foreach ($category_data as $cd) {
$cd_arr[] = $cd['category_slug'];
}
if(count($cd_arr) > 0){
$this->add_control(
'media_category',
[
'label' => esc_html__( 'Categories', 'plugin-name'),
'type' => \Elementor\Controls_Manager::SELECT2,
'multiple' => true,
'options' => $cd_arr,
]
);
}
$this->end_controls_section();
}