Battery health dropping

Battery Health & Performance 

Your battery health is fine and is undergoing normal usage. iPhone batteries, like all rechargeable batteries, are consumable components that become less effective as they age. You should change out the battery once your Battery Health reaches below 80% which will take over 2 years to reach under normal usage. Until then enjoy your iPhone.

Here is some more reading on an iPhone battery and its performance ➡️ iPhone Battery and Performance - Apple Support

Axel F.  

Pre-owned phone can have degraded batteries and processors that heat up quickly

The only thing that i can suggest is a repair or somthing.

:)

There is no evidence of an issue here.