I am facing the same issue after updating to the public beta of watchOS 11. Please let me know if you have any fix for this.

Update 3 Today, I updated to watchOS 11 beta 5 (22R5328e) and now the battery life is worse than the previous build. There is no way to roll back to a previous version of watchOS. I request Apple to please provide an option to roll back to a previous OS via iPhone or Mac.

Update 4: I have reset the watch 3-4 times, leaving it off for about 15-20 minutes each time. The battery drain issue seemed to be resolved initially, but it started again afterward. It's been 24 hours now, so it’s not an indexing issue. It seems like something else that the development team forgot to fix since the first beta.

Update: My friend has both the Apple Watch Series 9 and Ultra 2. Since he was working from home, I installed watchOS 11 beta 5 on both devices. Surprisingly, the Series 9 didn’t experience any battery drain issues and continued to perform well, providing a 2-day backup. However, the Ultra 2’s battery backup was reduced significantly, going from 3 days down to just 1 day.

Thank you, Apple, for not fixing the battery draining bug even in the 6th beta. It’s been over a month, and we’ve had to charge our watches three times a day. Why release a beta if you’re not going to address the bugs that users report through the Feedback app? I never expected this from a company like Apple. Yes, it’s our fault for installing the beta, and yes, it’s our fault for trusting the Apple development team. Thank you. This will be my last post. 🙏🏻