iPhone 12 battery health dropping fast?

You need to stop obsessing over Battery Health. Batteries are consumable parts. With every full cycle charge, your Battery Health will decline little by little. This is what batteries do. ALL batteries. If your battery health dips to 80% or less within the first 12 months, you would have a warranty claim, but that is most unlikely.

See this link about maximizing battery health and again, stop obsessing over something which is expected and completely normal --> Batteries - Maximizing Performance - Apple

You’ve had the phone for 9 months. On average a phone that receives a moderate amount of use (charge overnight, every night, and don’t have to charge during the day to stay above 20%) will drop about 1% per month, so your battery percentage would be 91% today by that measure. Your battery is doing great!

我正在用谷歌翻译。

您好，谢谢您在 Apple 支持社区发帖。如果您是语汉语使用者，我们也有相应的支持社区。欢迎随时加入！https://discussionschinese.apple.com/welcome

Lawrence beat me to it. But he is absolutely correct. Your battery is doing great!

淡定，如果你买了AC+，你可以免费更换电池，而且电池本身就消耗品，如果担心电池消耗速度，就正确充电，正确使用。

感谢您的帮助和知情答复

你好，你会中文？还是通过翻译软件？不过用中文交流实在是太棒了，会让这个社区交流丰富起来，谢谢大家。