Explanation
Admins can remove user accounts from the Restricted entities page in the Microsoft 365 Defender portal or in Exchange Online PowerShell.
Remove a user from the Restricted entities page in the Microsoft 365 Defender portal In the Microsoft 365 Defender portal at https://security.microsoft.com, go to Email & collaboration > Review
> Restricted entities. Or, to go directly to the Restricted entities page, use
https://security.microsoft.com/restrictedentities.
Reference:
https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/removing-user-from-restricted-user