Why is my battery health dropping fast?

I bought my iPhone 11 four months back. The battery health currently is 98%.

It is normal. But you can ensure proper practices to keep battery life in good standing. Here are some points:

• Use genuine charger.
• Do not fast charge if you do not need to.
• Cut down on wireless charging as it may often generate heat that is not good for battery life.
• Do not overcharge or undercharge. Just use it normally. Do not stress thinking much about it. But one idea that I read at multiple places is to charge the iPhone upto 80-85% and replug it into charging when it is around 20-25%. In short, avoid both extremes (full and zero charges)
• If you use Personal Hotspot over Wi-Fi, game a lot, and do other intensive tasks, the battery might heat, which can degrade its life faster.

Summing up: It is normal. You keep using the phone like you do. Just make sure to keep the above points in mind to take a bit more care of the battery.

Hope it helps. :)