The ability to change notification tones for apps in Android is a native feature of the Android app. iOS removed that capability for users some time ago. If that feature is desired, iOS is where you need to inquire.
The ability to assign custom notification tones in Android based on the text of the notification received thru use of third party apps is also Android driven as they allow developers to develop apps that will operate on Android. iOS app development is much more restrictive and costly. That is why you do not see those apps from independant developers on iOS. Again, an Apple iOS restriction that has to be addressed to them.