Completely normal. My iPhone 13 was at 100% for 7 months and then on the 8th month, it went down 2%. The Apple battery health indicator is false and does not provide an accurate reading.

how long das you battery last?

Batteries is batteries. Who knows why these things happen? But they do. I don’t check battery health any more. I’ve no idea what it is on my SE2, bought mid-2021. When the battery obviously affects performance adversely, I’ll replace it.

You trippin dawg, don’t drain it below 30% and you’ll be fine

how much are you charging it? are you using it as a main phone?