Preload with mandatory/dynamic cookies

preload-cookies.php

add_filter( 'rocket_partial_preload_url_request_args', 'rocket_add_cookie_preload' );
add_filter( 'rocket_preload_url_request_args', 'rocket_add_cookie_preload' );

function rocket_add_cookie_preload( $args ) {
	$cookies = [
		new WP_Http_Cookie(
		[
			'name'  => 'cookie_notice_accepted',
			'value' => 'true',
		] ),
	];

	$args['cookies'] = $cookies;

	return $args;
}