Yes! Pushy supports notification delivery to Android & iOS devices worldwide including mainland China, and thousands of companies are already using Pushy to deliver notifications reliably in this region.
We built a notification gateway using MQTT to deliver notifications to Android & Electron devices worldwide. Therefore, we aren't impacted by the fact Firebase Cloud Messaging is blocked in China. Furthermore, our solution does not depend on Google Play Services, which most Android phones in China lack.
Note: Web Push for Google Chrome is blocked in China. There is unfortunately no way around this.