Battery health

I started using my new iPhone 12 mini around August 2022, and as of writing my battery health is at 96%. I am sure it was at 100% when I first started using it. I am aware that battery health degradation is normal, however I am concerned with two things primarily

1. The period of time. It does not seem right for the battery to degrade on average a percent per month

2. The trend on how it reduced. The health was at 100 till approximately 1.5 months ago and suddenly it stated dropping rapidly. I remember it being 97% just last week but it has already dropped another percent.

i have also noticed the phone heating up significantly when charging.

is this behavior and weird trend in the health normal? What can I do to prevent it from continuing?