Note this is less about Android being worse than iOS and more about the play store and Google services not being available in China, so people can't install the Microsoft Authenticator app from a trusted location.
At least, it is officially provided in Baidu, Lenovo, Huawei and Samsung app stores. And for other vendors like OPPO, Xiaomi, VIVO, I they also have this app as it is already widely used. Not sure whether it is submitted by Microsoft or is just copied by these vendors.
I think the main reason is some internal App will use Google services, which is not available in China.
Huawei is ditching Android compatibility via AOSP completely and their version of Google Play Services and switching to their own ecosystem called "HarmonyOS Next" which will be pure.
The big China players like Tencent QQ support it but there is no incentive for Microsoft.