How can I stop my iPhone 13 Pro Max screen from going black?

I have a phone 13 pro max, and l'd say probably a week or 2 ago I noticed I put my hand over some of my screen. It went completely black until I removed my hand from over the screen and then it would go back to normal. It don't lock the phone when it goes black. And this is not consistent it's happened a couple times l've noticed. And I can make it go black a couple times and then it won't let me do it anymore.

I would compare this too the setting in iPad. Where if you have a case with a screen cover on it when you put the cover on the screen it goes black and locks the iPad. and I added an imagine of the setting I’m referring to.

Thank you in advance for any help.

[Re-Titled by Moderator]