The goetta sandwich is built around a pork product that is mostly grain, and that ratio is the whole point. Goetta is ground pork, sometimes with beef, simmered with steel-cut oats and onion and pepper until it sets into a sliceable loaf, then chilled hard. It is not a sausage with filler. The oats are roughly half the mass, and they are what let a thick slab crisp to a deep crust on a flat-top while the inside stays soft, which is the texture the entire sandwich exists to deliver. A sausage patty cannot do this; the oat bind can.
The craft is in the fry and the slice. Goetta is cut thick from the cold loaf and laid on a hot, lightly greased flat-top, then left alone long enough to build a hard, browned crust before it is turned, because the oats want time and will go to mush if they are crowded or flipped early. That crust is the structure: it holds the soft interior together long enough to lift the slice onto bread. Cincinnati treats this as a breakfast build, so the carrier is usually plain toast or a soft roll that does not compete, with egg and cheese as the common companions and a little hot sauce or ketchup as the acid against the rich, peppery pork. The bread is deliberately neutral because the crisped goetta is the only texture that matters, and anything with real chew would fight it.
The variations stay inside the breakfast frame and the local pan. A version with cheese melted onto the crisped slice, one with a fried egg whose yolk does the work of a sauce, a build that runs goetta in place of bacon under egg and cheese on a roll. Goetta also sits on the wider regional-specialty shelf next to scrapple and livermush, the other grain-bound pork products that crisp the same way and stay tied to their own corners of the map. Those deserve their own articles rather than being crowded in here.