I'm trying to create a coiled part in Inventor 2026 but struggling to get it right. I've tried several methods but none quite work. Whatever way I create it, I need to be able to unfold it into a flat pattern.

Ideally, I would start with this:-
Then end up with this:-

The one in the image is a bodge. I've used a coil command to create a single turn of a rectangular section then extruded the end pieces. This is roughly right but I can't unfold it into a flat pattern &, if I could, the end pieces would be dog legged.
Can anyone suggest a method that might work?