Using the uninstaller you can remove SDL from your PC. Please run the uninstaller from the account used to install SDL to ensure the Windows Shell is restored.
To uninstall SDL go to C:\Steam Deck Launcher and open unins000.exe
To open the uninstaller without being able to use the Windows Shell (eg black screen when logging in) open the Task Manager by pressing CTRL + ALT + DELETE from the options select Task Manager, press Run new task and enter C:\Steam Deck Launcher\unins000.exe
For information on manual uninstallation and how to remove SDL from a different account visit: