if you’re doing something like checking once in a while, why not put the native code in appcontroller.mm that unity generates? right after the controller is allocated do your checks, if its time to ask, the alert will show up
Hi, I think you can try to use a plugin called UniRate in the Unity asset store. It can help you prompt the users automatically with a simple drag. And it works for both iOS and Android. You can find more detail in this forum post.
As far as I know, there is not a way without calling native method to pop up a system window, so maybe you have to use a plugin.