Computer Configuration > Administrative Templates > Microsoft Edge
Both
HKLM\Software\Policies\Microsoft\Edge
Enforces a minimum Restricted Mode on YouTube and prevents users from picking a less restricted mode. Set to 'Strict' to enforce Strict Restricted Mode on YouTube. Set to 'Moderate' to enforce the user to only use Moderate Restricted Mode and Strict Restricted Mode on YouTube. They can't disable Restricted Mode. Set to 'Off' or don't configure this policy to not enforce Restricted Mode on YouTube. External policies such as YouTube policies might still enforce Restricted Mode. Policy options mapping: * Off (0) = Do not enforce Restricted Mode on YouTube * Moderate (1) = Enforce at least Moderate Restricted Mode on YouTube * Strict (2) = Enforce Strict Restricted Mode for YouTube Use the preceding information when configuring this policy.