Hello - that image is blurry but sure looks like it could be SubD to me… meantime your surface has a problem here with some point messiness that I think I’d clean up before proceeding -
A VariableBlendSrf might be OK -
but he ends/edges do not appear to be planar in your image, nor quite as round as what Diego shows with a BlendSrf, which means it is likely to be a bit of work - but adding a knot to the BlendSrf may allow it to be flattened somewhat to match what the image shows - still, easier in SubD, Rhino 7 Feature: Subdivision Geometry
-Pascal