It is NEVER Ctrl+Alt+S, it is always Win+Shift+S.
Not sure how you got it to work with the wrong key combo, but you probably had third party tools to remap the keys. They were never native to Windows to begin with.
If you still prefer using Ctrl+Alt+S, download PowerToys from the Store app, and use the Keyboard Manager feature in PowerToys to remap it back to Ctrl+Alt+S as you wish.