Open the Shortcuts app
Tap the plus icon to create a new shortcut
Tap Add Action
Search for Open App and select it
Tap App and choose the app you want
Tap the share icon or the three dots
Tap Add to Home Screen
Tap the app icon next to the shortcut name
Choose Photo, Choose File, or Take Photo
Select an image or icon with the color you want
Rename the shortcut if needed
Tap Add
Repeat for each app you want to customize
Use the new shortcut icons on your Home Screen
Remove the original app icon from the Home Screen if desired