My 11 Pro Max battery seems to drain battery since 15.2.1 please advise

Try a Hard Reset:

1. Press volume up (quickly)
2. Press volume down (quickly)
3. Press and hold the power button until the Apple logo ( ) appears

▷ Battery performance guide.

If the battery health somehow manages to fall below 80%, get expert service and support at the Genius Bar.

▷ Call 1-800-MY-APPLE or get help here. 

The fact that this made it out the door is VERY disappointing. Apple Devs make too much money for work like this.

In my case, it looks like the home app is draining 57% of my fully charged battery in about three hours.