remove device from my account
How do I remove my Apple TV 4K device from my account?
Apple TV 4K (3rd generation)
To remove a device from your account, see the following.
Log into https://appleid.apple.com/account/manage
Then in the Devices section click on your device.
To remove a device, click on the Device name and then click Remove from account.
Or go to Settings > [username] > [device name] on an iPhone or iPad.
Or go to Apple menu > System Settings > [username] > [device name] on Mac.