Any idea what are the alternatives? Dont see similar offerings from AWS or Azure.

One minus point for Firebase is its Android SDK relies on the availability of Google Play services. Most of Android phones in China has no Google Play. So apps can not run even when you do not utilize any of Google Play services. In addition, there is no official words that you can use Firebase services within the great China firewall. It's better to look elsewhere if you have China market in mind.