Although the battery health is good, my Apple Watch's battery is draining rapidly after the latest WatchOS update. How can I prevent such fast battery drain on my watch?

The rate at which a device's battery loses its charge or depletes its energy over time is referred to as battery drain. Battery drain refers to how quickly a device's battery discharges or runs out of power while in use or even when idle in the context of electronic devices such as smartphones, tablets, laptops, and wearables (such as smartwatches).
There are several ways to fix your Apple Watch's rapid battery drain, especially after updating to the latest WatchOS:

• Turn off and on your Apple Watch to power cycle it. Unexpected battery drain is often fixed by this simple step.
• Reset Sync Data: If the problem persists, open the Watch app on your paired iPhone, select General, and reset. Select Reset Sync Data. No notification will be sent when this process finishes. If data corruption prevents contact and calendar sync, this step can help. It resets the watch data and syncs.
• If the previous steps don't work, try unpairing and pairing your Apple Watch with your iPhone. Your settings and watch faces are usually backed up when unpaired. When repairing the watch, you can restore them. Although more complicated, this step can help with persistent battery drain.
• Be Patient with WatchOS Updates: After an update, the latest WatchOS may perform background tasks and optimizations. Normalizing your watch's battery consumption may take several days. During this time, your watch may drain its battery quickly, but it should return to normal usage.