After upgrading my phone to Android 10.X(Q OS) version, my wearable device’s battery gets used up rapidly.

Samsung is aware of this symptom which may appear on Wearable device supporting Samsung Pay such as Gear S3, Galaxy Watch, Galaxy Watch Active, and Galaxy Watch Active2 due to compatibility problem between Q OS and Watch plug-in of Samsung Pay.

And this issue has already been resolved with a new Watch plug-in update which is available now at Galaxy Store.

Samsung encourages users to keep your software and apps updated to latest version.