If you want to prevent a customer initiating a given action on a subscription, you can remove the button from the My Account > View Subscriptions page.
Be aware that removing cancellation buttons can have legal implications. For example, California has an Automatic Renewal Law which requires stores to provide an easy-to-use mechanism for cancelling. Before removing cancellation button, we recommend you discuss potential implications with a legal professional.
The following plugin demonstrates how to remove a button using the 'wcs_view_subscription_actions' hook. By default, only the Change Payment Method button is removed, but you can uncomment additional actions to remove other buttons.
If you want to remove a feature entirely from WooCommerce Subscriptions, you should follow the guide on disabling core subscription features as removing the button does not disable the feature completely.
Note: We are unable to provide support for customizations under our Support Policy. If you need to further customize a snippet, or extend its functionality, we highly recommend Codeable, or a Certified WooExpert.