Display all posts randomly

Hi blaivas

If related is set to false it displays related posts by post date, instead of by terms in common. But they are still related by the terms.

You could get your own related posts with this filter
https://keesiemeijer.wordpress.com/related-posts-by-taxonomy/filters/#related_posts_by_taxonomy_pre_related_posts

Put this in your functions.php file.

add_filter( 'related_posts_by_taxonomy_pre_related_posts', 'rpbt_override_related_posts', 10, 2 );

function rpbt_override_related_posts( $related_posts, $args ) {
	// Use widget or shortcode settings for our own query.
	$post_args = array(
		'post_type' => $args['post_types'],
		'posts_per_page' => $args['posts_per_page'],
		'orderby' => 'rand',
	);

	// Format thumbnails needs a meta query for posts with post thumnails.
	if ( 'thumbnails' === $args['format'] ) {
		$post_args['meta_query'] = array(
			array(
				'key' => '_thumbnail_id',
			),
		);
	}

	$my_related_posts = get_posts( $post_args );

	return $my_related_posts;
}

This will get random posts with the WordPress function get_post()
https://developer.ww.wp.xz.cn/reference/functions/get_posts/

I’m sure there are plugins that do this out of the box for you.
https://ww.wp.xz.cn/plugins/display-posts-shortcode/