Account supervision or device controls?
Account supervision follows a managed account into supported services. Device controls apply rules on a particular phone, tablet, computer, or console. Many households need both.
Account supervision
A supervised Google account can carry Family Link and YouTube settings into supported Google services. The rule depends on the child using that account.
Device controls
Apple Screen Time can manage an iPhone or iPad. Microsoft Family Safety can manage connected Windows, Xbox, and Android activity, with web filtering tied to Edge. Installed products add their own device and browser requirements.
Where gaps appear
A guest account, another browser, signed-out television app, or unsupported operating system can sit outside the chosen layer. Map these routes before deciding that one dashboard covers the household.
A practical combination
Use the managed child account for service-level settings, then add operating-system rules for apps, websites, purchases, and schedules. Test both layers from the child profile.