I never had such significant battery degradation after one year. My iPhone 15 Pro Max right now:
Battery health - Normal
Max Capacity - 100%
Cycle Count - 213
I don’t use the 80% max charge setting. The iPhone gets its charge daily during the night between 3:30 and 6:30 am via the Belkin Boost Charge Pro 3-in-1 Wireless Charger (the charger is sitting behind a smart plug that turns the power on and off at the times mentioned above).