In smartphone screens, Samsung may be all about OLED, but it's steered away from using those kinds of displays for its TVs, instead using LCD and QLED tech. It has unveiled a super-helpful (and not at all borne out of self-interest) way to check your display for the major issue as part of its efforts to remind people that OLED may be susceptible to burn-in.
Its YouTube video shows the types of visual vomit that you should be looking for when checking for burn-in (pixel discoloration due to static images). It includes a 10-second static red display that fills the TV and should make the screen's burnt-in parts more apparent.
In reality, or as widespread as Samsung could have you think, the OLED burn-in concern is not quite as clear-cut. Evaluation by editors of Engadget and others has shown that such displays can be quite reliable. Characteristics such as pixel / screen shift (which constantly moves the entire image by a pixel) and logo luminance reduction (which dims static parts of the image, such as a network logo or scorecard in a sports game) also help to reduce the likelihood of burn-in.
If your screen has burn-in, it will likely be clear enough without having to look for 10 seconds at a solid color on the Display. Additionally, Samsung is more than happy to sell you one of its QLED screens that it says is free of the burn-in plague. Nevertheless, samsung has had its own issues with OLED displays elsewhere— it used the technology in its Galaxy Fold monitors.