Judging by what I see, you have applied symmetry, but the semicircle has remained in its position.

If I'm right, I'd say redo the symmetry by being sure to include the semicircle, or at this point, apply symmetry (a horizontal flip) on its own to invert the positions of the up and down points.

If the origin of the problem is the symmetry you suggest @Sylk, maybe simply reversing the normal of the support plane of the semicircle sketch can solve the problem... to be checked.

Yes @Silver_Surfer , I was about to add it in my post, but I had a doubt, I'm not sure that changing the normal will return the sketch horizontally. To be checked, indeed

Hello For my part I will create 2 sketches on staggered plans so no more problem, the construction is clean. Modification possible without error, symmetry possible, facetization configurable without worries, same for sheet metal jigs

I just understood why you were talking about symmetry. I didn't do any symmetry to build my piece, I reversed the dimensions and attached some sketch constraints.

Wouldn't it be simpler to build the smoothing in 3D sketches. Point selection is possible, and you can create trajectory lines... The only small constraint is that you need as many segments in the initial sketch as in the arrival one.

You have to select the sketches close to the points that need to be connected (no matter the order)

If you find yourself like in your case with the departures and arrivals that cross each other, you go to one of the points and you drag it to the right arrival point and this changes the smoothing.