iOS has extensive settings that allow you to control and restrict what content your kids are allowed to see, what they are allowed to purchase, what apps they can use and even how much screen time per app they are allowed. The Apple TV doesn't have quite the same amount of parental controls, but you can still certainly block in-app purchases, restrict viewing content and set some other boundaries.
The "Up Next" section of the Apple TV app is a useful feature that helps you keep track of what shows you are watching and where you are in each show. So if you've been watching 20 different shows across Apple TV+, Netflix, Amazon Prime, Hulu and Disney+, you should be able to see at a glance that you are on episode 5 of The Mandalorian and season 2 episode 8 of The Handmaid's Tale and so on.
Apple Arcade offers unlimited access to over 100 titles with a free trial and monthly subscription. Most titles support the use of a gaming controller, which brings the Apple Arcade experience closer to that of dedicated gaming consoles. Even regular App Store games can be easier to play with a controller, instead of touching the screen or using the Apple TV remote.
The Apple TV has a single HDMI output for one display. There is no built-in support for multiple TV screens, or for showing different content on different displays.
Playing the same content from one Apple TV to multiple screens is possible with an HDMI splitter. These are sold separately and come in different configurations.
The Apple TV and Apple TV 4K can be personalized for different users sharing the device. Once different user accounts are created, each person watching Apple TV will enjoy their own profile with viewing histories and recommendations. While switching accounts does not change the app layout on the home screen, it will customize the Up Next and other sections of tvOS based on viewing habits. You can switch Apple TV profiles with two clicks on the Siri remote.