Yes, this one works well and seems are very softened.
However, they are still visible, even with a diffuse, as my normals are not as strong as yours.
I wanted to make something like a calm lake surface, not something as “frosted” as the one in your screenshot.
I suppose I have to come back to panning normal maps.
Anyway, thanks for your help. At least I learned some tips! Could be useful in other cases.