1. disable FTP commands from config.php
2. add to config.php

// Update core
define( 'WP_AUTO_UPDATE_CORE', true );

optionally for Synology NAS

# reset chown for Synology user nobody
chown -R nobody:nobody /web/wordpress/dir

# reset files and folders chmod in /web/wordpress/dir
find . -type f -exec chmod 0644 {} \;
find . -type d -exec chmod 0755 {} \;