Luki99 I think the light is only necessary for the separately available camera or to visually distinguish controllers when there's more than 1 player. The regular Bluetooth signal goes through my black isolation tape without problems. If you know you have a history of peripheral flickering lights causing symptoms, I highly recommend to give it a try.
However, I can feel that the PS4 video output is worse when compared to the PS3. The symptoms for me are similar to using Firefox (left eye hurts, headache over time). I'm not sure what they (Sony) do and why they do it. Happens in the system menu and in the one game I have tried so far (Assassin's Creed Origins). They give big epilepsy warnings every time you turn on the console but do nothing to make their video output clean in the first place.
I will try different games, too, and share oscilloscope pictures of the controller flicker as soon as I feel like looking at it again. 100% PWM is never a joy for me.