Use $_SERVER['host'] as URL

functions.php

<?php

add_filter( 'wl_website_jsonld', function( $jsonld ) {

	$schema = is_ssl() ? 'https://' : 'http://'; // set_url_scheme() is not defined yet
	$url = $schema . $_SERVER['HTTP_HOST'] . '/';
    
	$jsonld['@id'] = "$url#website";
	$jsonld['url'] = "$url";

	return $jsonld;
} );