IPhone 7 battery usage time problem

Left iPhone 7 standby overnight and go settings check the battery usage time is 2 hours. I'm not sure what cause my iPhone 7 running in the background.

Added (1). Charged my iPhone 7 to 100% and let it on Airplane mode, low power mode on & Wi-Fi off standby overnight without touch it.
But when I wake up and go settings check the battery usage time is 2 hours. I'm not sure what cause my iPhone 7 running in the background.
I have tried learn from internet and reset my phone, but the problems still exist.
May I know anyway to solve it?

You might need to change the battery, go to an IPhone store and ask then to take a look at it

Could (in that same section) see what apps were running & how long. Maybe some app had a process that caused that.

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