I was looking at Cardassian starships recently, and it hit me that all of them (Galor, "thicc Galor," Hideki, and the freighter) have that forked design element. It made me wonder if the fork is a feature of their version of warp drive...perhaps some sort of "tuning fork" to project and control the warp field.
On combat starships (Galor, Hideki) the "tuning fork" is mounted at the stern; maybe for maximum maneuverability "within subspace" or for safety concerns? Meanwhile, the freighter has it mounted at the fore since it's hauling heavy loads...I've read that having the engine pull instead of push the mass of the ship would make for a more stable space vehicle (this theory was used when creating the ISV Venture Star in James Cameron's Avatar).
The only outliers are the transport Bok'nor (a reuse of the "Merchantman" model) and the dreadnought missile from Voyager...
*I like to think "Merchantman" type ships in the Alpha/Beta Quadrants are a common design churned out by many cultures on the cheap; maybe the Cardassians purchased or copied the design from another power.
*perhaps the dreadnought carries its "tuning fork" internally?