Jan Koch

Upon activation, this plugin uses the “automatic_updater_disabled” filter to prevent automatic updates from being installed. 
It does not offer configuration, not even an options page in WP Admin.
Simply install and activate the plugin to disable all automatic updates. Deactivate the plugin to re-enable all automatic updates.

Stop Automatic Updates

This plugin disables all automatic updates. No configuration needed.

KZeni

Disables the default notification emails sent by a site after an automatic theme and/or plugin update. Simply activate the plugin to disable these email notifications (allows failure notices through unless setting is enabled to disable these as well).
This is a simple & lightweight plugin that simply uses the official filters made available as of WordPress 5.5 to disable these email notifications upon activation. It does let update failure notifications through by default, but the Settings => General page has a setting to disable these as well.
Check things out on GitHub at <a href="https://github.com/KZeni/Disable-WordPress-Theme-and-Plugin-Auto-Update-Emails" rel="nofollow ugc">https://github.com/KZeni/Disable-WordPress-Theme-and-Plugin-Auto-Update-Emails</a>

Disable Theme and Plugin Auto-Update Emails

Disables the default notification emails sent by a site after an automatic theme and/or plugin update. Simply activate the plugin to disable these ema …

Stop Automatic Updates vs Disable Theme and Plugin Auto-Update Emails