Add below code in wp-config.php . This will disable all automatic WordPress core updates.

define( 'WP_AUTO_UPDATE_CORE', false );

Disable automatic plugin updates by adding below code in function.php. If you need to do for specific plugin. you can add this filter to the respective plugin file

add_filter( 'auto_update_plugin', '__return_false' );

Disable theme updates. add in theme function.php

add_filter( 'auto_update_theme', '__return_false' );