Phone still won’t turn off

If the following procedure does not work:

… Force restart iPhone - Apple Support

(And you do need to be quick about the button presses)

then use the Get Support link in the upper right of this webpage, and discuss your options and alternatives with Apple.

Robbiness wrote:

all icons won’t open

Follow the forced-restart procedure previously linked.

Click or tap on the following: Force restart iPhone - Apple Support

That procedure uses the side buttons, not the display.

Using the side buttons and not the display does require you to be quick about the button presses, so removing any protective case might help.

If using the side buttons to restart fails, contact Apple Support, using the Get Support link at the upper left of this webpage.

Can you go to Settings > General > Shut Down and do it.