Hello, I am beta tester years now. I phone owner for last 8 years (several devices) and I think this drain is on purpose. 3 months now they didn’t fix it, there is no excuse. Sent many times feedback about batter drain. They see all those treads and still nothing. That’s why you battery health is falling. I ve seen new devices and batteries losing health in some months, while older iOS did it in years. Conclusion: Many owners will buy new battery and then new phone. Wining from batteries and new devices. All for benefit. I would advise you to downgrade as long as you can keep your phone. I will buy android, apple is not respecting customers.