Same here, my phone is brand new just 3 days and the battery drains very fast. My 4 years old 11 Pro Max at its 77% capacity can hold the charge better than this one, it's so frustrating. I lock the phone, put it on airplane mode, disactivate location and all background updates, NO use at all and still the battery goes down!!
Hope they can fix it with a software update and it's not a faulty batch needing replacement, because honestly that would be so disappointing. I can't imagine with Apple Intelligence the battery will run out in a couple of hours. I expect from this new phone battery to last at least a day and a half with a light use :( and being a light user I've stretched it up to 24 hours on a weekend, but now that I'm at work and I need to use it it doesn't seem that it's going to last until the end of my working day.