There are these topics:
https://forum.defold.com/t/using-adaptive-icons-for-android-builds/28686
https://forum.defold.com/t/create-adaptive-icons-for-android/69375
They’re pretty helpful, I’m following this setup right now, I hope to get it working anytime soon 
The bulk of the work is creating the icons themselves which is not that easy if you aim for the pixelated look 