Hello.
Confirm your current working environment: Remotely connecting to Windows 10 from the OptiPlex host is feasible, remotely logging into Windows 11 is not.
Check that the local client account (OptiPlex host login account) has been added to the remote desktop user group.
May I know what is the error message when you fail to log in? Is it the same as the picture below?
We look forward to your reply so that we can help you accurately analyze the problem.
Best regards
Jacen