Why I phone 14 pro max Battery draining soo fast after updating to ios 17?

Hello -qff_,

There can be many causes to see a lower than expected battery. We'd recommend going through the following article in detail to cover all of the bases: iPhone Battery and Performance - Apple Support

This covers everything from usage to health, so it can help shed some light on what's happening.

If you have any questions with your findings, let us know more details and we can continue.