I worked on a project in Umbraco CMS where I needed to remove product variants from shopping carts when they were deleted, since Umbraco doesn't offer an out-of-the-box solution to notify when a product variant has been deleted. By using Umbraco's notifications and creating a custom NotificationHandler, and managed to keep the carts updated by removing these variants, improving the user experience. For more details, you can check the guide at https://alexhovy.dev/umbraco-notifications-how-to-handle-removing-commerce-product-variants/.