Yes. It does.As someone with a Tandem OLED iPad pro, burn in does not exist. This will be the same when it comes to Macs.
Even the OLED iPhone and Apple Watch does not have burn in.
I’ve had burn in on two of my iPhones. 13 Pro Max and now 15 Pro. Subtle, but it’s there.
I don’t keep it at full brightness, and I don’t use AOD.
The M4 iPad Pro is too new to be used as a baseline for whether or not burn in exists. The real test will be in years two, three, four and beyond.
But even then, an iPad’s usage is not the same as a laptop’s, generally. (Though, sure, you can use a Magic Keyboard, etc or trackpad and mouse with it.)
Either way, burn in does exist. I’ve experienced it. My clients have experienced it. If you haven’t, I’m glad.