I have a problem with forming a sheet metal from an intersection of a circular profile surface with no planar edges.

I can able to extrude this as a base flange in sheet metal but later on, I need to flatten it in order to make some modifications to the side edges with cutting which I can do by flattening at the end of the feature tree but need to see this when it is unflattened.

1st step - Referencing from geometry as I indicated without any flat face by intersection curve

2nd step to base flange and extrude it to a specific dimension and try to cut extrude the side edges with a red color sketch.

3rd step - In order to cut the side surfaces; since I cannot use flatten as it will suppress my modifications after the unflattening process, I tried to use Unfold command. This command requires a fixed face (which I have only arc faces) tried to manipulate the program by adding one more short flat surface to be able to get the fixed face.

4th step - Unflattening and make some modifications, but finally, I couldn't figure out how to unfold it again as I have already cut my flat surface :/

5th step - As a plan B- I suppressed the unfolding and try to cut extrude again with using normal cut with the sketch that I want to use from the flatted surface

6th step - The final result was a broken far edge surface in below image whereas I could get closer what I want which in flatten the view.

I could, of course, split from the middle and mirror it however the holes and other circular dimensions will have a projected line which will not be precise and accurate. This below image is just to show what my requirement will look like (at +Z axis direction)

Could you be able to have a solution to this as I see many techniques where the bent edges are known in advanced and controlled which is not referenced from a specific surface as I indicated in the beginning?