renderCallback.php

<?php
//... 
	register_block_type( 'block-list-post-type/block-list-post-type', array(
		'editor_script' => 'block_list_post_type_scripts',
		'render_callback' =>  'block_list_post_type_render',
		'attributes' => [
			// ...
		]
	 ) );
}

// ...
function block_list_post_type_render($attributes) {
	$args = array(
		'post_type'   => $attributes['selected'],
		'posts_per_page' => 6,
		'post_status' => 'publish',
	);
	$entity = new WP_Query( $args );

	$entityList = '';
	while( $entity->have_posts() ) :$entity->the_post();
		$entityList .= '<li><a href='. get_permalink().'>'. get_the_title() .'</a></li>';
	endwhile;
	wp_reset_postdata();

	return  '</ul>'. $entityList . '</ul>';
}