read somewhere that maybe they’re preparing for OLED screens
All iPhones since the iPhone X (2017), and not the iPhone SE line, has an OLED display. iPad Pro also has OLED.
If it is that crucial, they should add a few pixels of margin around the entire desktop, and randomly shift everything around. Doing only corners and not straight edges, and doing it by a fixed per-app amount, seems a bit silly.
How does that argument work?