What is newer? I’ve seen S7, 8 and 9 with burn in. So maybe S10? Seems typical to me. How many devices do you get to see and use on a regular basis? Myself, I get to see and use over 200. A small sampling of a much larger whole but more than most.
You can’t see the burn in because it’s on a lighter background. Throw up a darker background and it’s there. I assure you.
Either way, you’re free to have an always on display. I prefer not to.
I’ve owned over 100 phones since the old bag phone days. Many of them with OLED displays.
I’ve NEVER had one with burn in. Never.