wp-redirect-login.php

<?php
add_action( 'admin_init', 'szbl_redirect_subscribers' );
function szbl_redirect_subscribers()
{
  $redirect_url = site_url( '/where-to-go/' );
  
  if ( is_user_logged_in() )
  {
    if ( !current_user_can( 'edit_posts' ) )
    {
      wp_redirect( $redirect_url, 303 );
      die;
    }
  }
}