Disable Automatic Updates in WordPress without plugin.
Disabling auto update of wordpress core files without using plugin. For disabling wordpress auto update without plugin you need cpanel or FTP details for accessing wp-config.php file.
Start editing the wp-config.php file and add the following code to wp-config.php file. So that it will stop auto update of wordpress core file automatically.
define( 'AUTOMATIC_UPDATER_DISABLED', true );
And then save it that’s all here after your wordpress website will not be updated automatically.
Note : Disabling these updates is strongly discouraged by wordpress.