Sounds like you’d benefit from using Delaunay Triangulation algorithm. A whole bunch of libraries out there that support this. It wouldn’t give you those concentric rings in your second image if (say) you were to provide only the hull (outline) though but not sure if you need those. It would produce a cleaner mesh.
Whether this is useful to you or not, there’s a really nice post about it on these forums here .
It’s probably not relevant but we also added this feature for 2D physics . If relevant, you can also use Collider2D.CreateMesh to get a mesh from it.