iphone 14 pro stuck on locked screen, unresponsive, will not power down

Contained in the Related Article Link at the top of the page, which brought you here is the following:

If your screen is black or frozen

Follow the steps for your device.

On your iPhone 8 or later, including iPhone SE (2nd and 3rd generation)

1. Press and quickly release the volume up button.
2. Press and quickly release the volume down button.
3. Press and hold the side button until you see the Apple logo.
4. 

What happened when you tried this very specific action?

When I change screens When I swipe up the screen doesn’t show. It does same when I push the button the right. My question is this what locks the screen?