Mac can’t remember Passwords
Why does my iPhone SE remember every password of every device it connects to and always can log in. But my MacBook and Apple TV and other devices don’t even attempt to remember a password.
Your Mac can utilize Your Apple Keychain to remember passwords and iCloud can keep these websites and passwords synced between your iPhone and Mac. I don’t know how Apple TV retains ‘passwords’ as you switch among your various streaming apps, but it is somewhat rare when you revisit a streaming source and have to enter a password.