I finally 'get' equivalence

I know you said that but you are wrong.

yes it does get 4 times more light but it has to cover a 4x larger sensor so in the end each pixel get the same amount of light.

If a FF camera has to expose a picture at f2, 1/60 second at ISO 200 a m43 camera will have to expose the same scene at f2, 1/60 second at ISO 200, the DR and noise will only be affected by your pixel pitch, given the sensor built is the same of course.

4x more light on 4x larger sensor it not an advantage unless each pixel can absorb more light.