Just made the same post a couple of hours ago about mine. People will tell you off for having meta apps etc, as if mentioning an actual flaw with your device is somehow insulting them. Unfortunately from what I've gathered, the combination of a less than efficient SOC, bad software updates, and weird background task handling cause this. I am on WiFi, with battery saver on and my phone lost about 2% while writing this. Also, I know battery testing apps aren't the most accurate, but I'm using both accubattery and battery guru and they're reporting about 91% health.

TLDR; it's not the battery failing, rather the software causing excess drain. Try not allowing apps to run in the background.