Default user on AppleTV
How can you change the default user on AppleTV device
Apple TV 4K (3rd generation)
Question marked as
You can change the default user by entering other information for the settings for default user (sign out for current account, sign in with other account).
If you are taking over a device from someone else, then you are advised to reset to factory settings instead, as a more thorough method. Reset or restore your Apple TV to its factory settings - Apple Support