Straight up widening the penis theory is not oft spoken on, as changing your natural shape is trickier than simple girth gains. I myself have a cylinder penis. I would prefer an oval shape however I have found no good means that I’m comfortable with trying.
A member here uses a cock ring and his palm on a waist high hard surface to do palm presses. I can’t recall where he detailed it. Another member or two have used rolling pins. Not something I’d ever recommend.
A method I heard tell of and attempted (and failed because I lack the grip strength and the threaded screws wouldn’t cooperate) is the “Red Zulu Crusher” or some such. This is a technique found on Mattersofsize forums and relies on two hard, flat surfaces being compressed evenly onto the top and bottom of the erect penis shaft using powerful spring clamps. I don’t know what a set is or the danger levels. Only that it is fabled that Shane Diesel used this method to create the girth profile of his incredibly thick penis.
Those are the only means I have run across and I personally wouldn’t try any of them, despite a real desire to get wider. As I fully agree with your visual assertion about what width looks like.