Since Microsoft is phasing out the Control Panel applets and trying to move them over to the Settings app gradually, the System applet too appears to have gone missing in Windows 11/10.

Open the Control Panel. In Windows 10 or Windows 8, select System and Security > Administrative Tools > Services. Windows 7 and Vista users select Systems and Maintenance > Administrative Tools ...

Microsoft has moved most of the features to Windows Settings. However, the Control Panel is still an important part, and if you often open it on your computer, you should try adding more options ...