WordPress page template redirects: https://extendd.com/plugin/custom-login-page-template/

redirects.php

/**
 * Function Name: front_end_login_fail.
 * Description: This redirects the failed login to the custom login page
 * instead of default login page with a modified url
 */
add_action( 'wp_login_failed', 'front_end_login_fail' );
function front_end_login_fail( $username ) {
	$setting = class_exists( 'custom_login_pro_admin' ) ? get_option( CUSTOMLOGINPRO . '_settings' ) : get_option( CUSTOMLOGIN_PAGE_TEMPLATE()->id );

	// Getting URL of the login page
	$referrer = $_SERVER['HTTP_REFERER'];
	
	// if there's a valid referrer, and it's not the default log-in screen
	if ( !empty( $referrer ) && !strstr( $referrer, 'wp-login' ) && !strstr( $referrer, 'wp-admin' ) ) {
		wp_redirect( get_permalink( $setting['login_page_id'] ) );
		// Not working yet...
		add_filter( 'login_page_messages', function() {
			return 'FAILED';
		});
		exit;
	}
}

/**
 * Function Name: check_username_password.
 * Description: This redirects to the custom login page if user name or
 * password is empty with a modified url
 */
add_action( 'authenticate', 'check_username_password', 1, 3 );
function check_username_password( $login, $username, $password ) {
	$setting = class_exists( 'custom_login_pro_admin' ) ? get_option( CUSTOMLOGINPRO . '_settings' ) : get_option( CUSTOMLOGIN_PAGE_TEMPLATE()->id );
	
	// Getting URL of the login page
	$referrer = $_SERVER['HTTP_REFERER'];
	
	// if there's a valid referrer, and it's not the default log-in screen
	if ( !empty( $referrer ) && !strstr( $referrer, 'wp-login' ) && !strstr( $referrer, 'wp-admin' ) ) {
		if ( $username == "" || $password == "" ){
			wp_redirect( get_permalink( $setting['login_page_id'] ) );
			// Not working yet...
			add_filter( 'login_page_messages', function() {
				return 'ERROR';
			});
			exit;
		}
	}
}