Why is my new iPhone's battery health significantly degraded with 98% Maximum Capacity?

I recently purchased an iPhone, and I noticed that in the Battery Health & Charging settings, I am seeing an "Important Battery Message" stating that my battery health is significantly degraded. However, my Maximum Capacity is 98%, and the phone is only one month old.

I have already:

• Updated to the latest iOS version

• Restarted my iPhone

But the message is still there. Could you please help me understand why this is happening? Should I be concerned, or is this a software issue?

[Re-Titled by Moderator]