Yeah the whole consent thing is a bit all over the place hey? Google took a long time to come out with their generic Consent SDK and still has lots of legal speak around it's usage. Some of our clients use it but several have just opted for a simpler yes/no to personalised ads. I don't really know what's legal or not to be honest.
We still advise people to have a look through the policy and make their own decision, as it's something that you may have to defend or at least respond to. We are at least starting to seeing people request their data per GDPR.
You definitely need to do this on iOS and Android, and in fact any platform, GDPR is not platform specific.
You can modify the content of the consent dialog quite easily though if you need, it's just a html file packaged with your app, either directly on Android or in the bundle on iOS. This is useful if you want to modify it to reflect multiple sources of ads etc.
And yes our Adverts ANE has had the Consent SDK to detect a user's region and display the dialog both iOS and Android for a while now:
