If you want to unsubscribe from web push notifications, you can always do it in your browser settings.
Google Chrome example:
Open Google Chrome browser on your device.
Go to Settings.
Under "Privacy and security" click Site settings.
Click Notifications.
Choose to block or allow notifications: you can select a particular domain where you have previously allowed the subscription and remove it. You will no longer receive notifications from a site for which you have removed your subscription through browser settings.