Don’t shame the man with the extra digit projecting from his thenar eminence.

If you reach for the top left corner your thumb will naturally come into contact with the bottom right corner of the screen, assuming you are holding the device one-handed (in your right hand).

I’m trying to picture this, but I can’t. If I hold and lock my iPhone with my right hand, I press the lock button with my thumb. If I try to reach the top left corner, I either do that with my left thumb (mostly) or index finger (sometimes), or with my right thumb (very awkward movement on a Pro Max). In none of these cases my right thumb comes in contact with the screen or even close to it. Maybe because I use the backside of my pinky finger to lock the phone in place.

I think he meant your palm hits the screen, which does happen to me sometimes.

The right hand large stretch with the thumb into the top left area - the pad below your thumb on your palm can make contact with the screen.

You can also trigger the camera by swiping right-to-left on the lock screen or from the notification pull-down.