WPML redirect from /?lang= to /lang

Redirect.php

<?php
/**
 * Redirect class file.
 *
 * @package wtei-core
 */

namespace WTEICore;

/**
 * Class Redirect
 */
class Redirect {

	/**
	 * Init class.
	 */
	public function init(): void {
		add_action( 'template_redirect', [ $this, 'template_redirect' ] );
	}

	/**
	 * Redirect if old blog address is found.
	 */
	public function template_redirect(): void {
		if ( is_admin() || ! is_404() ) {
			return;
		}

		$url = isset( $_SERVER['REQUEST_URI'] ) ?
			filter_var( wp_unslash( $_SERVER['REQUEST_URI'] ), FILTER_SANITIZE_STRING ) :
			'';

		if ( ! $url ) {
			return;
		}

		$post_id = url_to_postid( $url );

		// phpcs:disable WordPress.Security.NonceVerification.Recommended
		if ( isset( $_GET['lang'] ) ) {
			$lang = filter_input( INPUT_GET, 'lang', FILTER_SANITIZE_STRING );
			unset( $_GET['lang'] );
			$post_id = apply_filters( 'wpml_object_id', $post_id, 'post', false, $lang );
		}

		if ( $post_id ) {
			$new_url = add_query_arg( $_GET, get_permalink( $post_id ) );
			if ( site_url() . $url !== $new_url ) {
				wp_safe_redirect( $new_url, 301 );
				exit;
			}
		}
		// phpcs:enable WordPress.Security.NonceVerification.Recommended
	}
}