WordPress: Don't use cookies with YouTube

functions.php

<?php
/*
Use YouTube privacy-enhanced mode. More info: https://support.google.com/youtube/answer/171780?visit_id=637419781721286051-946666784&rd=1
*/
add_filter(
	'embed_oembed_html',
	function( $cache, $url, $attr, $post_ID ) {
		if ( preg_match('#^https?://(www\.)?youtu\.?be(\.com)?/#i', $url) ) {
			return str_replace(
				' src="https://www.youtube.com/embed/',
				' loading="lazy" src="https://www.youtube-nocookie.com/embed/',
				$cache
			);
		}

		return $cache;
	},
	11,
	4
);