WP Job Manger change jobs url (NOT slug)

If you check out the output() method in the includes/admin/class-wp-job-manager-setup.php file, namely this part:

/**
 * Output addons page
 */
public function output() {
    $step = ! empty( $_GET['step'] ) ? absint( $_GET['step'] ) : 1;

    if ( 3 === $step && ! empty( $_POST ) ) {
        $create_pages    = isset( $_POST['wp-job-manager-create-page'] ) ? $_POST['wp-job-manager-create-page'] : array();
        $page_titles     = $_POST['wp-job-manager-page-title'];
        $pages_to_create = array(
            'submit_job_form' => '[submit_job_form]',
            'job_dashboard'   => '[job_dashboard]',
            'jobs'            => '[jobs]'
        );

        foreach ( $pages_to_create as $page => $content ) {
            if ( ! isset( $create_pages[ $page ] ) || empty( $page_titles[ $page ] ) ) {
                continue;
            }
            $this->create_page( sanitize_text_field( $page_titles[ $page ] ), $content, 'job_manager_' . $page . '_page_id' );
        }
    }

you can see that it’s creating a page, with the jobs slug (by default) that contains the [jobs] shortcode to list the available jobs.

So you should be able to simply create a page with the careers slug, that contains the [jobs] shortcode.