Both my LG Ultrafine 5k panels - IPS panels - have significant image retention/burn in around the edges. Practically, how much worse can OLED burn-in be?Burn-in is a function of brightness intensity and time. For typical OLED TV use, sure it's usually not a huge issue because the content is dynamic and a given area of the screen will not remain very bright constantly, except maybe the channel logo in a corner which modern OLEDs are programmed to identify and darken and that will typically change place as you change channel.
For desktop use, the situation is much different. Typical desktop UI and computer applications UI are much more static than TV content and have plenty of static elements which will be displayed for a long time at exactly the same place. Burn-in will happen much more quickly under those conditions than by watching varied content on TV.