Using an OLED with Windows Desktop will definitely still lead to burn in if you don't take care of it. Even the best OLEDs will have serious image retention issues. It might not be permanent, but even temporary retention can be quite bad and annoying.
When using a Windows PC on any OLED, be it TV or Monitor:
- Make sure the taskbar is set to auto-hide. Otherwise its an extremely static fixture on the display, and will be one of the first things to keep showing
- Try to avoid long periods of static images. Having MC up in Standard View for hours and hours might not be ideal, as unchanging elements can cause issues.
- Use screen saver/monitor off with relatively short timeouts
Personally, my PC connected to my OLED TV is largely running in Theater View only, which automatically dims on inactivity to help with burn-in, as well as using a relatively low screen-off timer. I have yet to see any retention due to these measures.
On the other hand, there is numerous reports of people using OLED PC screens who ignore such measures, where the taskbar and other permanent screen elements start being retained even after short periods.
In summary, OLEDs still need care to be taken. Using a short screen-off timer just in case you leave it on is the least I can recommend to avoid issues.