A custom post type with title support turned off

no-title-cpt.php

<?php

add_action( 'init', 'register_no_title_post_type', 10 );

function register_no_title_post_type() {
	register_post_type(
		'no-title',
		array(
			'labels'        => array(
				'name'          => 'No Title',
				'singular_name' => 'No Title',
			),
			'public'        => true,
			'show_in_rest'  => true,
			'supports'      => array(
				'editor',
			),
		)
	);
}