Create Desktop Shortcut to Startup Disk for macOS (Preference Pane)
If you are looking for quick double-click action to open Mac OS Startup Disk preference pane as a shortcut, follow the steps below.
1. Go to Mac Hard Drive -> System -> Library -> PreferencePanes.
2. Find StartupDisk.prefPane and Right-Click -> Make Alias.
3. Mac OS will automatically put the Startup Disk shortcut on your desktop. You can rename it to whatever.