Add custom cron schedules with filter `cron_schedules`. See https://maheshwaghmare.com/doc/wordpress-cron/

add-cron-schedules.php

<?php
/**
 * Add Cron Schedules
 * 
 * @todo Change the `prefix_` and with your own unique prefix.
 * 
 * @since 1.0.0
 * 
 * @param array() $schedules Existing schedules.
 * @return array
 */
if( ! function_exists( 'prefix_add_cron_schedules' ) ) :
    function prefix_add_cron_schedules( $schedules = array() ) {

        $schedules['every_ten_minutes'] = array(
            'interval' => 600, // 600 seconds means 10 minutes.
            'display'  => __( 'Every 10 minutes', 'textdomain' ),
        );

        return $schedules;
    }
    add_filter( 'cron_schedules', 'prefix_add_cron_schedules' );
endif;