I think the 14 and 15 series just have garbage batteries. I had a 13 pro max before this and it took over 2 years to get to this point. I charge via MagSafe every night but I have all the battery health preserving features turned on88%? Goodness gracious my iPhone 12 Pro is at 87% after four years plus. Now I have the 16 Pro which should last me to the day I die since I’m old.