I want to cancel my Apple TV subscription

See the instructions in How to cancel a subscription from Apple - Apple Support including the following:

If you don’t see Cancel, the subscription is already canceled and won't renew.

and

If you cancel a paid subscription, you can keep using the subscription until the next billing date.

If needed, also see: If the subscription that you want to cancel is not listed - Apple Support

Another option is to use an internet browser to cancel as described in How to cancel Apple TV+ - Apple Support

Cancel apple tv