Applying polygonal extrusion method to a curve with multiple spline elements

Technical Support Geometry Nodes
2

Try zeroskilz’s setup here in the first post (the UPDATE)

with your example

1
11910×936 133 KB

Edit
Ahhhh it does get a slight glitch with even thickness on

2
21828×947 145 KB

Probably worth looking through that thread there are other methods with their pros and cons.