What you may be mistakingly calling “burn in” is likely actually “temporary image retention.” However, unless one sits and games for 8 hours straight on an OLED TV, this is unlikely to be an issue. (Certainly a potential use scenario, just not one for me.) This scenario is even less likely on a phone. I’ve had zero TIR or BI issues with my LG OLED (2016), my OLED Apple Watch, or my 10+ yr old Plasma. Maybe I’m just “lucky.” Or maybe it’s just not a problem.