iPhone 15 Pro Max Battery health

The typical Apple Battery will last about 2 years with normal usage. When your battery reaches 80% Battery Health, it will be time to make an appointment at the nearest Apple Store for Battery Replacement.

Stop trying to micromanage the battery; only long term changes are meaningful, because batteries are chemical processes, which are not as neat as digital processes. It is what it is. As you near the end of your warranty (1 year standard, 2 years if you purchased AppleCare+) check to see if it is near or below 80%. If it is make an appointment to have the battery replaced.