Data stored only on your device (favorites, history, settings) is never uploaded unless you signed in, and is removed whenever you uninstall the app or clear its data — deleting your cloud account doesn't affect it and it isn't retained on the server.
After a deletion request is completed, nothing associated with your account remains on the sync server. Standard server backups may retain residual data for up to 30 days before being purged.
See the Privacy Policy for what data the app handles, and the Terms of Service for the terms of use.