iPhone 7 Plus, all buttons not working

So, my iPhone 7 Plus is completely unresponsive.

First all the buttons were not working (Home button was working)

Silent switch, Volume up/down and power button was completely unresponsive.

So I shut down the phone through assistive touch.

I thought by plugging it in, the phone will turn on.

But when i plug it in a battery indicator is shown indicating full charging on the phone.

The battery screen is shown when plugged in, when I remove the charging cable, the screen turns off completely.

My phone has been plugged in for over an hour, with the battery indicator.

Any info will be of great help.