AppIcon - OneUIProject/OneUI-Design-Library GitHub Wiki

Most Samsung app icons are made of one solid background color and a white foreground icon, which sometimes also has a small detail with a similar color to the background color.

I would suggest you to use @color/primary_color for the background color and either @color/launcher_foreground_detail_color , @color/secondary_color or @color/primary_dark_color for the foreground "detail" color, so the color theme from ThemeUtil also applies for the app icon (exept for dynamic color themes).
The sample app icon for example: