After tweaking the shortcut to your liking, hit Add to make it part of your home screen. The original app icon will still be there, but you can hide it from the home screen to avoid confusion.

Now, it's back to the Shortcuts app again, to create the home screen shortcut for the new dark icon. Here, tap the Plus icon from the top to create a new shortcut and choose Open App as the action.

Launch the Shortcuts app on your iPhone or iPad, then tap the + icon in the top-right corner of the screen. Tap Add Action, then use the text field to search for Open App. Select Open App. Tap App.

Now, open Shortcuts and tap the + button at the top to create a new Shortcut, then select the Open App action. Tap the blue "App" text in the "Open App" action, then choose the app whose icon you ...