iPhone 15 Pro Max battery health at 92% after 415 cycles

Batteries, like people are individuals. No two people age exactly the same and batteries don’t age the same either. The exact usage, chemical makeup, storage conditions, exposure to heat and cold and about a dozen other factors mean that every battery ages differently. Battery aging is not a linear (straight line) and degrades at different rates as the chemicals in the battery age and other factors mentioned above. Apple expects your battery health to be at 80% after 24 months. If your battery health misses that expectation, contact Apple Support.

Please review the Apple Support articles on battery optimization. It contains the best  current practices for battery charging.

iPhone Battery and Performance - Apple Support

Batteries - Maximizing Performance - Apple

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

It is doing well.

To learn about maximizing (and the difference between) battery life and lifespan, read this support document --> Batteries - Maximizing Performance - Apple

Read this support article about iPhone battery and performance to learn about the battery health feature and what is considered normal performance --> iPhone battery and performance - Apple Support

To see the feature go to: Settings > Battery > Battery Health

"A normal battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles when operating under normal conditions. The one-year warranty includes service coverage for a defective battery. If it is out of warranty, Apple offers battery service for a charge." A degraded battery may display the notice: "Your battery’s health is significantly degraded. An Apple Authorized Service Provider can replace the battery to restore full performance and capacity." If it is not at or above 80% "normal", consider contacting Apple about a battery replacement. --> iPhone Battery Replacement - Apple Support

According to the above quoted information, you could be losing almost 2% per month the entire first year before Apple would deem this to merit a warranty replacement.

Your phone is doing fine. On average, iPhone Battery Health declines 1% per month of ownership. It's not linear and can remain steady for a while, then decline a few points. But the average loss is 1% per month. Since you say you've had your phone about a year, it wouldn't be unusual for your battery to be at 88% by now, so 92 is actually pretty good.

One thing you can count on is Battery Health to go only one direction and this down. When the time comes it dips to 80%, which it will if you own your phone long enough, it will then be time to pay Apple to replace the battery.