My iPhone's battery health is reduced to 97%

That's actually pretty good. My iPhone is just about a month older than yours and I have 90% battery life. Battery life is affected by how often you charge your battery and other factors. More information here: https://support.apple.com/en-us/HT208387

Tl;dr If the battery health is more than 80% then you have nothing to worry about it.

Maximum battery capacity measures the device battery capacity relative to when it was new. A battery will have lower capacity as the battery chemically ages which may result in fewer hours of usage between charges. Depending upon the length of time between when the iPhone was made and when it is activated, your battery capacity may show as slightly less than 100%.

A normal battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles when operating under normal conditions. The one-year warranty includes service coverage for a defective battery. If it is out of warranty, Apple offers battery service for a charge. Learn more about charge cycles.

Source: https://support.apple.com/en-us/HT208387 (iPhone Battery and Performance)