iPad Pro M4 battery life with Pencil use

My new iPad Pro M4 (11”) battery seems to be running down faster than it should.

Yesterday it was at 100%. I spent 3-4 hrs using the Apple Pencil.

This morning it was 30%. After another 30 mins of Pencil use this morning it was down below 10%

Is this normal? The drop from 30 to 10 seems especially fast.

I have it in the case that comes with the ESR keyboard, maybe that’s heating it up too much?