Actually, it is your display. OLEDs, while great for their per-pixel lighting and perfect blacks, cannot get very bright, which significantly dulls the effect of HDR. That means that on an OLED, some of the main benefits of HDR, like realistically bright specular highlights or expanded “color volume” (the combination of the size of the displayable color palette and the range of possible luminance of each of those colors) are not nearly as impactful as they are on an LED TV that can get extremely bright. OLEDs also cannot hold their brightness for as long as LEDs can, and so they all use ABL (Automatic Brightness Limiter) to dim the picture if a bright scene is on the screen for more than a few seconds.
LEDs, on the other hand, can go very bright. The TV I run FS 2020 on is a Sony X930E (a 2017 model) which can exceed 1,500 nits of brightness, and can hold that level of brightness pretty much indefinitely. Most OLEDs can only reach about 400 to 600 nits, and they can only achieve those levels for a few seconds before ABL kicks in and dims the picture.
The practical effect of this is that HDR on an LED TV is spectacular and lifelike. In flight sim, the sky is realistically bright and the sun glinting off the aircraft, off glass buildings, off distant lakes or streams, etc. produces realistically sparkling highlights. The additional color volume produced by the ability to go so bright also enhances more subtle effects like fog and haze. On my TV, if I’m flying and suddenly turn toward the sun or catch a sudden large reflection off the exterior of the aircraft it’s actually bright enough to make you squint, just as you would instinctively do in real life. It’s hard to describe if you haven’t experienced it, but HDR on an LED TV with a high maximum luminance capability just makes everything look far more real and gives it greater depth.
Most 4K Blu Ray discs are mastered at 4,000 nits, and the Dolby Vision standard supports up to 10,000 nits, so you can see how important the developers of HDR content think brightness is to the equation. Sony has demonstrated micro-LED TVs that can reach 10,000 nits, though they are so far only prototypes or very expensive units for commercial use, but it’s only a matter of time before that technology filters down to consumers. Micro-LED is already available to regular consumers, but more in the 1,500 to 2,000 nit range so far.
Not to knock OLED, because it definitely has its strengths (and there is no perfect TV technology - each involves trade offs), but OLED’s ability to wow you with HDR is severely compromised when it can only produce a few hundred nits versus LEDs that can display a few thousand currently, and mastering standards that anticipate luminance levels as high as 10,000 nits eventually.