Meanwhile, thanks to Burrman for all the valuable advice ..... as for Michael's approach, it is very valid and I tried it directly on the model .... but, certainly because of me, it does not give me back the shape right.

The space between the upper quadrant of the mudguard and the small one is why the shape is not found .... if you see the space of the fold (mirror side) it is practically nothing .... if I use the sweep to create that small space then not I can get to the bigger bend ..... obviously maybe it's me who doesn't know the right technique .... that's why I'm asking for help :)