worst possible scenario effectively trying to burn in the screen

calibrated to 200 nits brightness

Wut?
At that there shouldn't be any sort of burn-ins ever.
(That monitor can do '250 nits full screen, 1,000 nits max HDR')

(Also just 8 hours per day, dark taskbar (the only static thing in his case), monitor goes to slep after 2 hours of inactivity.)

This doesn't help my use-case at all :(.
It's not a stress test by any measure, the only "extreme" thing he is doing to it is "not allowing it to go to sleep after a few minutes of inactivity".

Sweet

almost a non-issue

tl;dr there's still burn-in but it's supposedly not very noticeable until you use the device for > 5 years

I have an Alienware OLED (AW3423DW). I've been using it for almost a year now. I use it for ~13h a day, for work, gaming and media (YT, TV shows, movies). I have HDR enabled in Windows and I use the monitor in HDR1000 mode.

I left the taskbar on for a few months and it got burnt in. I also got burn-in from watching content that is in 16:9 ratio (the monitor is 21:9). The monitor also got a defect, in the form of a thick line that is brighter that anything else that runs across half the top of the monitor left to right.

Despite this experience I would still buy OLED because IMO the brightness and colors are worth it but I also warn everyone that they WILL get burn-in if they want to use it to its full potential and all day long.

OLEDs are not there yet. Maybe in a few years or decades we'll get actual burn-in proof OLEDs

I have an early LG OLED. It's ten years old. Still looks amazing with the exception of red burn in.

It's not too bad, but it's noticeable