Could you explain how the guidelines are stricter on iOS? I’m not familiar with Apple guidelines.
Btw, just to give a bit of context for the Dynamic Icons: In Android, the notification icons need to be monochrome. Samsung is the odd one out and allows colors.
As such, devs are already sort of expected to develop a monochrome variation of the App Icon to be used as the notification icon. using the same design for the Dynamic Icon shouldn’t really ask more from developers. Issue is that some devs don’t even do the bare minimum, some apps just use a filled circle as a notification icon cause they forgot to check it.
Plus, there was a whole category of monochrome Icon Packs in the Play Store. I personally used Whicons for instance. So, making it official also helps with that.