I have an iPhone whose screen turns on but doesn't respond to touch. Could this be a software issue? This is my first post on this StackExchange community, so I apologize in advance if my post doesn't meet community standards.
An immediate family member recently started having a bizarre issue with her iPhone: its screen works, displaying the lock screen with no visible signs of damage after pressing the power button, but it doesn't respond to any screen input (touch, swipes, etc.). I've tried to force-restart the phone three times, but the screen is still unresponsive to input. I've also consulted this Apple discussions thread, but I'd like to rule out any software issues before seeking a repair with Apple.
Some specific details about the iPhone and the issue at hand:

The iPhone is a 64 GB iPhone 11 (not Pro).
The iPhone's iOS version (seemingly) can't be determined since I can't unlock the phone and hence access the Settings app or have it be detected by a computer. I'm guessing it's running iOS 13.x or 14.x.
The owner of the iPhone recalls the screen initially working perfectly fine, but ceasing to do so after pulling it out of her pocket.
The screen seems to be intact: no dead pixels, no obvious physical damage, etc.
All the buttons work.

Could this be an issue with the iPhone's software? If so, what are some potential causes, and how can I address them?
P.S: if you'd like more details or context, please don't hesitate to ask in the comments.
The only software &quot;issue&quot; that I can think of is the guided access, which e.g. parents can use to restrict their children while using the iPhone. However, I am quiet sure that it is disabled by default, once you restart the iPhone by forced reset (press lock-button and volume-down-button simultaneously for a couple seconds).
In addition, you could delete everything and make a factory reset with iTunes. But could not help at all, if it is not a software issue.
Furthermore, the guys at the apple store are really helpful and have special tools for diagnosing problems. As far as I know, as long as they just diagnosing the problem, the consulting is free.