iPhone battery capacity dropped

This is a user forum, you are not addressing apple here  just  fellow users

have you read About the battery and performance of iPhone 11 and later - Apple Support

and maybe iPhone Battery and Performance - Apple Support

and Batteries - Maximizing Performance - Apple

people report apple does not change the batteries until they are lower than 80% in health

That’s normal “wear and tear” on the battery.

1% per month is generally considered to be entirely “normal.”

Don’t obsess over short-term fluctuations.

Long-term trends are what’s significant.