How can I get a refund for an unwanted CapCut app purchase from Apple?

In most cases all transactions in the App Store are final. At times, Apple may provide a compassionate refund, but it should never be expected.

When starting a free trial, you saw the trial period on the screen, subscription start date, subscription price, and the message that says to avoid charges, you must cancel the free trial 1 day before the end date of the free trial. That is exactly what you agree to when you double clicked the side button to authorize the start of the free trial.

If you cancelled after you were charged, then you cancelled too late to avoid the charge. You now have the subscription you previously agreed to and cancelling will prevent it from renewing. It makes no difference if you use the service or not, the same way you would be charged for a Netflix subscription if you watched any of the shows or not.

You can certainly contact your bank to dispute the charge, but be prepared for that payment method to no longer be valid for any use in the App Store. Disputes are due to fraudulent charges, and for this charge it is something you agreed to and also verified with FaceID/Passcode.