Since the Apple Watch was first launched in 2015, it has never been supported on Android devices. The smartwatch's connectivity has been locked to the Apple ecosystem. This may change with Xiaomi soon.
Why? Xiaomi is rumored to be looking to expand its HyperConnect support. Right now, HyperConnect only supports fast file transfers, opening Keynote files, and broadcasting the contents of the Xiaomi 15's screen to a MacBook screen. In the future, Xiaomi is said to want to make the Apple Watch, AirPods, and HomePod compatible with their devices.
It's still unclear how Xiaomi will do this. My guess is that Xiaomi will develop a dedicated app for the connection. Hopefully, Xiaomi won't use the Nothing method that connects users' iCloud accounts to third-party servers from macOS devices.