12 pro max battery health dropping fast

All batteries degrade over time. Apple does not consider that an iPhone battery requires replacement unless it cannot maintain, at least, an 80% charge after 500 full recharging cycles. There appears, from your post, nothing wrong with your iPhone's battery.

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

Yes, nothing is wrong with your phone's battery. If you are still concerned, pay a visit to your local Apple Store or Apple Authorized Service Provider and have them take a look. Alternately, you can contact Apple Support directly by using the "Get Support" link in the upper right-hand side of this forum's web page ... but, don't be surprised if they tell you the same thing as I have already told you.

This is normal. Batteries degrade with use

About battery health on your iPhone - Apple Community

You're very welcome!