We looked into supporting integration with all iOS devices but unfortunately, Apple mobile products are not optimized for this type of integration. The process to integrate with 3rd Party push notifications is extremely lengthy and complicated and in the case of iOS, it only works with iOS apps, so we are currently unable to offer PushSubscribe on those devices.
However, notifications will function on Safari, when utilized on a MacOS desktop device! And definitely keep in mind - 90% of web users are on firefox and chrome, including on Android!
In fact, according to several reports, 70% of mobile users globally use Android.