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 …

Sakthivel S

This plugin is used disable the wordpress functionality of updating core, themes & plugins automatically. Also it will disable all kind of update notification from wordpress.org theme/plugin repository.
Features 
* Disable WordPress core, themes, plugin update 
* Disable notifications for all updates available.

Disable All Updates & Notifications

Disable Wordpress, Themes & Plugins Updates along with their update notifications.

Disable Theme and Plugin Auto-Update Emails vs Disable All Updates & Notifications