My iPhone 11 Pro Max is holding up REALLY well so far - it's been halfway around the world twice, on a dozen or so airplanes and literally hundreds of trains, all caseless and screen-protector-less. It's still absolutely perfect. I think I did find one very tiny scratch, MAYBE, which is only visible in direct sun if you angle the phone so that the sun is almost directly reflected into your eyes. But since that is not very good for your eyes, I wasn't able to spend enough time studying it, to confirm. It maybe have just been dust.
So far, extremely impressed by this phone's durability.