If you observe excessive heat from your TV display, rest assured that this is normal for OLED TVs.
*Do note that this does not indicate a defect nor does it affect the reliability or life of the product.
Unlike traditional LED TVs that utilize backlight technology, either in Direct-lit or Edge-lit types, which can distribute heat evenly, OLED TVs use self-lit technology. Each pixel will emit light source on its own which is positioned behind the surface panel. The absence of additional layers to mask the heat in OLED TVs means that user will experience more heat directly from the display than their LED counterparts, explaining the warmer feel during usage.
What might help:
1. Turn the TV brightness lower
2. Changing the Picture Mode settings to "Standard"