Most LEDs are based on a “blue pump”, which means the chip produces a lot of intensity in the blue wavelength range. Color temperatures are produced by adding more phosphor to the chip surface. The phosphor only allows certain wavelengths of color through, and the more phosphor added means the LED will appear warmer in color. More phosphor means more expensive though, which is why lots of LEDs are produced in the 7 to 5k range. Even when adding more phosphor to the chip and having a warmer color temperature, there is still blue light being produced and that can impact your sensitivity. Companies such as BIOS Lighting produce chips that don’t use a blue pump. Long story short, it’s a really complicated field that is long overdue for multiple layers of government regulation.

There are a lot of good articles about it. Explained in a rudimentary way, it’s super hard to make good reds for LED and has been a problem since its inception. OLEDs use little organic red pixels and the blacks turn off all light instead of replicating a black. It’s super interesting. When I was in school, they brought a major LED inventor to show us what they had, it wasn’t good quality light at the time and for a long time afterwards. OLED was the first time I saw good reds. If you go to a costco, look at the difference between the reds on the same pic, can you tell there is a difference or does it all look sort of magenta? That’s how you can tell if it’s a good OLED or not. To be fair though, you can mess with the settings to make it look shitty which some stores do to sell more of a certain type of tv.