I must say, super great anser and so fast, I did not expect this!
Cura beta arachne is really top, and within a layer there is no longer jumping. It is only jumped between the layers from time to time, but that does not bother me.
Since I want to design the cookie cutter tool I think your hack is not so helpful.
Another question:
As soon as the single top wall is printed, the print occasionally stops at the layers and there are small gaps (see picture). This is probably also because in CAD the wall width is 0.6mm and the nozzle also has 0.6mm, but as you described the model is translated into triangles and therefore is probably partly below the 0.6mm and then the print stops. For me this makes no sense because the function "print thin walls" is active.
I also find it interesting that the flow decreases in the upper part even though there is no script and the flow is constant at 110%. (See picture 2)
Do you know here maybe also know a workaround?