Advice on dividing and unwrapping this mesh I'm working on a project with several objects like this and they are causing me a lot of frustration.  I'd like some advice on the best way to divide faces and unwrap an object like this.  I've tried dozens of versions and I can't get away from mesh artifacts.  I believe the primary challenge is getting the mesh divided into relatively consistent quads. Shading smooth cleans up the faceting but introduces the stretch marks. Shading flat eliminates the stretch marks but the arches are faceted again.  I've run into this in the past and it is an area that I'm obviously lacking some basic information and experience.

This object is architectural and will have a smooth concrete texture applied in Unity.  It has a bevel modifier:

Smooth shading:

Flat shading:

Undivided mesh:

An attempt at manually creating quads:

Basic triangulation that results in long tri's&quot;

Again, I've done many versions.  These are just representative of the basic attempts. I'd love some &quot;best practices&quot; workflow advice on this.
It may be worth noting that the basic shape was created in Sketchup since I can draw consistent arches in 3 clicks.  It was then imported as an .obj and the face was extruded to the current shape.
To improve the shading:

either check ✓ Harden Normals in the Bevel modifier.
or slightly inset the area


FunFact: I'm not quite sure why this helps, it'd be great if someone explained it in the comments :)