my phone will not power on

Try a forced restart and see if that fixes it.

Quickly press and release the volume up button

Quickly press and release the volume down button

Then hold the side button until you see the Apple Logo on the screen.

Let go of the button and let the phone start up.

Maybe this Apple document will help

If your iPhone, iPad, or iPod touch won't turn on or

is frozen

https://support.apple.com/en-us/HT201412