In most cases transactions in the App Store are final. At times Apple may offer a compassionate refund, but it should never be expected. You gave permission to debit money when you double clicked the side button with the amount showing on the screen, followed by verification with FaceID or Passcode, so it is not something that can be done by accident. If you signed up for a free trial, that would meed to be cancelled by you at least 24 hours before the trial ends to avoid any further charge.
It makes no difference if you use the app or not. I subscribe to HBO/Max and have to pay whether I watch any of the shows or not. That is simply how subscriptions work for any business. Make sure you have cancelled the subscription here to avoid any future charges:
If you want to cancel a subscription from Apple - Apple Support