Battery health issue

I purchased my iphone se 2020 on 1st jan 2021 and my battery health dropped from 100% to 98% on 6th april 2021 which is weird.Also i take care of my battery health so much i never let my phone battery goes below 20% and i never let my phone heat. I always use 5w apple.In just 3 months it dropped to 98%😕