Thanks for your answer dirge0matic. Yeah, the smoothing help a bit but it is still definitely not enough.

Finally, i gave up this solution as i think it cannot work if you try to smooth the external ring while it’s already connected with the “ray”. The ray connection “attracts” the faces to him when using the subsurf modifiers as it calculates angles based on the connected vertices around.
Finally, i smoothed the ring separately then applied the modifer and then only connected it to the “ray”.
It helps even if not ideal as i had to apply the modifier (making it non-reversible).