@Frank_Burner, you won’t see anything happen when you start Roon Server on any computer, it just runs in the background. The Roon Remote application (roon.exe) is what is now used to control the Server.
That said, have you looked at this thread in case Roon and Roon Server are set to compatibility mode on your W11 PC:
Compatibility mode should be turned off for the Roon applications.