Because you chose white, you are measuring the response time of phosphors not the LED. So your tests are not what you thought.
Back when I designed CRT monitors and TV sets I could find out the response time of each type of phosphors.
In LEDs (white) there are many types of white. Blue-white, Red-white, warm, natural, etc. Each have a different mix of phosphors. There is more than one way to mix up "warm white". The LED companies will not tell me what mix they are using. In a CRT the response time was important. Because no one is using white LEDs 'fast' to send data, the response time is not important and not measured and certainty not in the data sheet.
Phosphors materials turn on pretty fast, but they turn off much much slower. For radar displays we used some that had a decay time of 6 seconds. For data terminals I have used as slow at 100mS to typically 5mS. CRT phosphors is refreshed 60 times a second. It has been a long time scene I thought about phosphors response time, I know I have used fast phosphors I do not remember their time but I can't believe they are much faster than 0.1mS.