Hello,
Make sure you are using Windows 11/10 Professional or Windows 11/10 Enterprise to install RSAT tools. You also must be using an Administrator Account.
Kindly check if the below thread and article can help:
RSAT is not installed on Windows 11 - Microsoft Q&A
RSAT Tools Installation Error - Microsoft Community
RSAT Tools missing after 1909 update & not in FODs or "Add a Feature" - Microsoft Community
Remote Server Administration Tools | Microsoft Learn
Best regards,
Karlie Weng