Those shortcuts should work in the lateset LrC 11.3 version.
Try resetting your LrC preferences file as detailed in the below article. It can resolve many unexplained issues such as this one. Place a copy of the current Preferences file on your desktop so it can be easily restored if the issue persists. Then reinstall LrC 11.3 and see if the shortcuts now work properly.
The keyboard shortcuts for Rotate Left and Right shown by the menu commands Help > Library and Develop Module Shortcuts is wrong for many languages. The table below, extracted from TranslatedStrings, shows the incorrect help entries in red:
LR 11.3 made changes to the shortcuts for many languages, so it's even more important that the Help is correct. E.g. see this thread:
Google translation: "Lightroom did not allow me to use the shortcut: shift + M to rotate images. Does anyone have the same problem?"
LR 11.3 silently changed the keyboard shortcuts for Rotate Left and Rotate Right in many of the supported languages. In Spanish, French, Italian, and Swedish, they are now Shift + W and Shift + Q.
The shortcuts shown by the menu commands Help > Library and Develop Module Shortcuts are wrong -- I've filed a bug report here about that:
While reverting to LR 11.2 will restore the old Spanish shortcuts, it appears the changes in LR 11.3 were deliberate and unlikely to be changed back in future versions of LR.
Updates to the Adobe Photography Products were released on June 13. The update contains a fix for this issue.Please download and the latest version of your application via the Adobe Creative Cloud Application or your respective device app store.
If you do not see the update (Mac and Win) you can refresh your Creative Cloud App with the keyboard shortcut [Ctrl/Cmd]+[Alt/Opt]+[ R ].
Note: App store availability can take several days for the update to appear and be available.
Updates to Adobe Photography Products were released today and contain a fix for this issue. Please refresh your Adobe Creative Cloud App ([Ctrl/Cmd]+[Alt/Opt]+[ R ]) and download the updated version “.0”.