Sign in With Google - Adjust redirect after successfully authenticating

redirect_after_register.php

<?php
/**
 * functions.php
**/

add_filter( 'siwg_auth_redirect', 'redirect_users_after_login', 10, 1 );

/**
 * Filter the url redirection after user authenticates with Google.
**/
function redirect_users_after_login( $redirect_url ) {
  // Always redirect users back to home page.
  return get_home_url();
}