Don't sign up directly. Sign up as Apple TV "channel" which forces the streamer to provide the subscription through Apple's App Store and the beautifully pro-consumer subscription management it offers: reminders you're on the subscription, transparency on the plans and pricing, one click cancellation, all in a one location.

Of course, if devs are intending to make money from subscriptions, devs may rationalize how devs should be in control of the user's subscription instead of letting the user pick Apple because users trust Apple will balance power for users.